Police are urging prospective MPs not to canvass alone and to take “active steps” to protect themselves following an unprecedented increase in abuse and death threats.

For the first time, written safety advice has been sent to all candidates standing in next month’s general election, as every police force in the country prepares safety briefings.

Joint advice from authorities including the National Police Chiefs’ Council (NPCC), Electoral Commission and Crown Prosecution Service advises would-be MPs to seek advice on security measures at their homes and workplaces.

The document calls for candidates to contact police if they fear for their safety, or are the victims of offences including harassment, stalking, malicious communications, vandalism, hate crimes or false statements against their character.

It details “potential signals that behaviour could be escalating”, including the release of personal information online and “fixated ideas”.

General election: On the campaign trail Show all 114 1 /114 General election: On the campaign trail General election: On the campaign trail Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire AFP via Getty General election: On the campaign trail A sculpture of an owl is bedecked with an EU beret as Liberal Democrat leader Jo Swinson gestures during an interview at a general election campaign event in Bath AFP via Getty General election: On the campaign trail Boris Johnson (C) talks during a question and answer session on a general election campaign visit to Ferguson's Transport in the town of Washington, west of Sunderland AFP/Getty General election: On the campaign trail Boris Johnson tries to save a shot during a warm up before a girls football match while on the campaign trail in Cheadle Hulme, northwest England POOL/AFP via Getty General election: On the campaign trail Jeremy Corbyn makes cup of coffee as he campaigns in Barry, south Wales AFP General election: On the campaign trail Nicola Sturgeon poses as she launches the SNP campaign bus tour, at Queensferry Crossing in Edinburgh, Scotland AFP via Getty General election: On the campaign trail Boris Johnson reacts as he changes a wheel of a Formula One car during a Conservative Party general election campaign visit to Red Bull Racing in Milton Keynes POOL/AFP via Getty General election: On the campaign trail Britain's Prime Minister Boris Johnson visits a Christmas market in Salisbury REUTERS General election: On the campaign trail Liberal Democrat Leader Jo Swinson on the election campaign bus on route to Chelmsford PA General election: On the campaign trail Labour leader Jeremy Corbyn talking to a university worker outside Birkbeck/SOAS University of London, at the announcement of his parties of the plan for the extension of workers' rights PA General election: On the campaign trail Nicola Sturgeon plays a game with string during a visit to Perth and District YMCA Getty Images General election: On the campaign trail Brexit Party leader Nigel Farage picks up a copy of The Brexiteer during a visit to JPI Printers in Dinnington PA General election: On the campaign trail Boris Johnson, centre, talks to veteran James Gammer as he visits a veterans centre AP General election: On the campaign trail SNP supporters meet First Minister Nicola Sturgeon following her address during a St Andrews day election speech Getty General election: On the campaign trail Jeremy Corbyn has a photo taken outside Birkbeck/SOAS University PA General election: On the campaign trail Liberal Democrat leader Jo Swinson during a visit to the Cardiff United Synagogue PA General election: On the campaign trail Brexit Party leader Nigel Farage reacts as he attends an election debate ITV/Reuters General election: On the campaign trail Jeremy Corbyn wears a jacked displaying Labour's slogan 'For the many, not the few' EPA General election: On the campaign trail Prime Minister Boris Johnson on The Andrew Marr Show Getty General election: On the campaign trail Nicola Sturgeon plays with local children during a visit to the Jelly Tots & Cookies Play Cafe in Uddingston, South Lanarkshire PA General election: On the campaign trail Opposition Labour Party leader Jeremy Corbyn eats some chips in Whitby, northern England AFP via Getty General election: On the campaign trail Boris Johnson and Conservative MP George Eustice, left, tour 'Rodda's Clotted Cream' whilst campaigning in Cornwall Getty General election: On the campaign trail Jo Swinson during a visit to Dunkertons Cider Company, an organic and plastic free brewery in Cheltenham PA General election: On the campaign trail Jeremy Corbyn holds up unreacted documents with NHS staff. Mr Corbyn released uncensored official documents which he says provides confirmation that the NHS is on the table in trade talks with the USA EPA General election: On the campaign trail Nigel Farage meets locals in Barnsley market PA General election: On the campaign trail Nicola Sturgeon launches the SNP's general election manifesto Getty General election: On the campaign trail Labour Party leader Jeremy Corbyn addresses the audience during the launch of Labour's environmental policy in Southampton Getty General election: On the campaign trail Boris Johnson tries an apple as he visits Healey's Cornish Cyder Farm in Callestick AP General election: On the campaign trail Jo Swinson helps make a chicken tikka masala during a visit to the Ashoka restaurant in Bearsden, Glasgow PA General election: On the campaign trail Nigel Farage playing golf on a range at One Stop Golf in Hull PA General election: On the campaign trail Jeremy Corbyn addresses the audience during a climate emergency rally in Falmouth Getty General election: On the campaign trail Liberal Democrat leader Jo Swinson meets supporters during a visit to Dunkertons Cider Company PA General election: On the campaign trail Boris Johnson visits Chulmleigh College AP General election: On the campaign trail Labour Party leader Jeremy Corbyn as he appearing on the BBC political programme The Andrew Neil Show. The opposition leader defended his handling of anti-Semitism allegations after Britain's most senior rabbi suggested the issue was a "new poison" within the party that had been "sanctioned from the very top". In an unprecedented intervention ahead of next month's election, Chief Rabbi Ephraim Mirvis suggested Corbyn was "unfit for high office" due to his perceived failure to clamp down on the problem within the party BBC/AFP via Getty General election: On the campaign trail Liberal Democrat leader Jo Swinson alongside Julian Dunkerton, whose father founded and ran Dunkertons Organic Cider, during a visit to the company's organic and plastic free brewery in Cheltenham, Gloucestershire, whilst campaigning for the General Election. PA Photo. Picture date: Tuesday November 26, 2019. See PA story POLITICS Election. Photo credit should read: Aaron Chown/PA Wire Aaron Chown PA General election: On the campaign trail Prime Minister Boris Johnson launches the Conservative Party Scottish Manifesto in North Queensferry Getty General election: On the campaign trail Britain's Opposition leader Jeremy Corbyn poses with WASPI (Women Against State Pension Inequality) supporters after he outlined Labour's plans to repay the "historical debt of honour" owed to women born in the 1950's AFP via Getty General election: On the campaign trail Jo Swinson alongside the Lib Dem's candidate for Truro and Falmouth, Ruth Gripper, and founder of Finisterre, Tom Kay, during a tour of the British surfing brand, which creates sustainable surfing gear, in St Agnes, Cornwall PA General election: On the campaign trail Prime Minister Boris Johnson poses with sheep as he visits the Royal Welsh Showground, in Llanelwedd PA General election: On the campaign trail A coalition of NHS (National Health Service) campaigners led by "Keep Our NHS Public" and "We Own It", pose for photographs with masks of US President Donal Trump, right, and Prime Minister Boris Johnson carving up the NHS with a giant knife and fork, as they take part in a demonstration on Parliament Square. The campaigners are calling for the NHS to be taken "off the table" in a trade deal with the US by ending privatisation in the health service and restoring it to a wholly publicly owned and provided service AP General election: On the campaign trail Brexit Party leader Nigel Farage visits Plymouth Fisheries at Sutton Harbour Getty General election: On the campaign trail SNP leader Nicola Sturgeon gives her party's candidate for North East Fife Stephen Gethins a haircut, during a visit to Craig Boyd Hairdressing in Leven PA General election: On the campaign trail Vans belonging to The Community United against Labour Party anti-Semitism group, Culpa, parked next to a police car ahead of the Labour Race and Faith Manifesto launch Getty General election: On the campaign trail Boris Johnson prepares to serve food at the Royal Welsh Showground PA General election: On the campaign trail Jeremy Corbyn tries his hand at bricklaying during a visit to the West Nottinghamshire College Construction Centre, in Ashfield PA General election: On the campaign trail Liberal Democrat leader Jo Swinson during a visit to the London design museum to discuss the party's tech policy PA General election: On the campaign trail Brexit Party leader Nigel Farage visits Seaham Getty General election: On the campaign trail Britain's Prime Minister Boris Johnson arrives for the Conservative party's manifesto launch in Telford Reuters General election: On the campaign trail Labour Party leader Jeremy Corbyn meets supporters during a visit to Thurrock in Essex PA General election: On the campaign trail Protesters wait for the arrival of Prime Minister Boris Johnson ahead of the launch of his party's manifesto PA General election: On the campaign trail Jo Swinson gestures from atop a crane during a visit to an eco home building site in Sheffield AFP via Getty General election: On the campaign trail Jeremy Corbyn meets a supporter on a train on his return from a visit to Sheffield PA General election: On the campaign trail Prime Minister Boris Johnson during a visit to Bassetlaw District General Hospital in Worksop, Nottinghamshire PA General election: On the campaign trail Nigel Farage campaigns in Hartlepool Getty Images General election: On the campaign trail Jeremy Corbyn outside an Amazon depot in Sheffield, to announce plans for a workers' rights revolution and to ensure big businesses pay their fair share of taxes PA General election: On the campaign trail Prime Minister Boris Johnson, Liberal Democrat leader Jo Swinson, First Minister of Scotland Nicola Sturgeon and Labour leader Jeremy Corbyn, during their successive appearances on BBC Question Time Leaders' Special at the Octagon in Sheffield PA General election: On the campaign trail Liberal Democratic Party leader Jo Swinson visits a primary school in Cambridge EPA General election: On the campaign trail Boris Johnson lays a brick during a visit to the Barratt Homes Getty General election: On the campaign trail Labour leader Jeremy Corbyn attends the launch of the party's election manifesto at Birmingham City University Getty General election: On the campaign trail Brexit Party leader Nigel Farage holds his party policy document during the party's policy launch in Westminster PA General election: On the campaign trail SNP leader Nicola Sturgeon joined Dundee East candidate Stewart Hosie to made a keynote speech at The Quay Getty General election: On the campaign trail Prime Minister Boris Johnson holds a part of an electrical appliance during a General Election campaign trail stop at Ebac in Newton Aycliffe AP General election: On the campaign trail Jeremy Corbyn poses during a visit to The Oatcake Boat on the Trent & Mersey Canal, Stoke Getty General election: On the campaign trail Jo Swinson and Willie Rennie Leader of the Scottish Liberal Democrats gesture, during a visit to Glasgow Reuters General election: On the campaign trail Prime Minister Boris Johnson during a visit to Jimmy Egan's Boxing Academy at Wythenshawe, while on the campaign trail ahead of the General Election. PA Photo. Picture date: Tuesday November 19, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA General election: On the campaign trail Liberal Democrat leader Jo Swinson (left) during a visit to the Gurdwara Singh Sabha Temple in Glasgow PA General election: On the campaign trail Labour leader Jeremy Corbyn meets Colin and his mother after a speech at the University of Lancaster Getty Images General election: On the campaign trail Britain's Green Party co-leaders Jonathan Bartley, Sian Berry, and deputy leader Amelia Womack, wave during the launch of the party manifesto at the Observatory at London Wetland Centre Reuters General election: On the campaign trail Scottish Nationalist Party leader Nicola Sturgeon meets voters and activists at Cafe Roma in Clarkston, Glasgow AFP via Getty General election: On the campaign trail Protestors participate in an anti-Boris Johnson rally in his constituency Uxbridge, west London AFP via Getty Images General election: On the campaign trail Brexit Party leader Nigel Farage looks out from a window on the Kestrel crabbing boat in Grimsby fish dock PA General election: On the campaign trail Prime Minister Boris Johnson on a tug boat in the port of Bristol PA General election: On the campaign trail Green Party Co-Leader Sian Berry has a selfie taken with a supporter at the Observatory, London Wetlands Centre PA General election: On the campaign trail Jo Swinson helps chef Leonardo Mastofilippo to make pizza during a campaign visit to cafe Amisha in South Bermonsey EPA General election: On the campaign trail Labour leader Jeremy Corbyn with WASPI (Women Against State Pension Inequality) ladies during a visit to Birkenshaw Sports Barn in Uddingston EPA General election: On the campaign trail Boris Johnson at the unveiling of the Conservative Party battlebus in Middleton, Greater Manchester PA General election: On the campaign trail Nicola Sturgeon sits alongside Cycling Without Age user Cyril Corcoran (centre), aged 78, in an electric tricycle during a visit to Hawick, in the Scottish Borders PA General election: On the campaign trail Nigel Farage holds a fish during a stop at the Grimsby Seafood Village PA General election: On the campaign trail Liberal Democrats leader Jo Swinson in the boxing ring at Total Boxer, a specialised boxing gym which offers training to young people as a means of keeping them away from violence, in Crouch End, London PA General election: On the campaign trail Britain's Prime Minister Boris Johnson reacts as he participates in a school art lesson, making a clay figure at George Spencer Academy, west of Nottingham AFP via Getty General election: On the campaign trail Labour Party leader Jeremy Corbyn during a visit to the Heart of Scotstoun Community Centre in Glasgow PA General election: On the campaign trail Scotland's First Minister and SNP leader Nicola Sturgeon visits the Cafe Gelato in Rutherglen, Glasgow EPA General election: On the campaign trail The Green Party launch in Bristol PA General election: On the campaign trail Farage enjoys some chips at the start of a nationwide tour for the 2019 general election, in Whitehaven AFP/Getty General election: On the campaign trail Labour leader Jeremy Corbyn unveils the Labour battle bus in Liverpool PA General election: On the campaign trail Boris Johnson reacts as he talks with workers whilst weighing packaged tea bags at the Tetley Tea Factory in Stockton-on-Tees AFP/Getty General election: On the campaign trail Brexit Party leader Nigel Farage on the campaign trail in Whitehaven, where he was confronted by Karl Connor PA General election: On the campaign trail Lib Dem leader Jo Swinson speaks to volunteer Rosie Squires in the Stainforth 4 All charity shop during a visit to Stainforth in South Yorkshire to meet people affected by flooding PA General election: On the campaign trail Nicola Sturgeon poses with candidates during the SNP general election campaign launch in Edinburgh Reuters General election: On the campaign trail Labour Party leader Jeremy Corbyn with Laura McAlpine, the party's candidate for Harlow PA General election: On the campaign trail Anti-Boris Johnson protesters demonstrate outside the hall where the Conservative Party were launching their campaign in Birmingham EPA General election: On the campaign trail Green Party Co-Leader Sian Berry (left), Deputy Leader and Parliamentary Candidate for Newport West Amelia Womack (right), and Bristol West Candidate Carla Denyer (centre) at the launch of the party's general election manifesto in Bristol PA General election: On the campaign trail The PM tastes whisky during a visit to Diageo's Roseisle Distillery near Elgin, Scotland Reuters General election: On the campaign trail Nigel Farage poses with boxer Dereck Chisora during a visit to a boxing gym in Ilford Reuters General election: On the campaign trail Jo Swinson visits a science class at Hinchley Wood School near Esher Reuters General election: On the campaign trail First Minister Nicola Sturgeon holds a guitar as she visits Dalkeith Community Hub Getty General election: On the campaign trail A man heckles as Jeremy Corbyn gives a speech at the Senior Citizens Hall in Macclesfield Getty General election: On the campaign trail Britain's opposition Labour Party leader Jeremy Corbyn visits residents affected by flooding in Conisbrough Reuters General election: On the campaign trail Boris Johnson gestures as he helps quality control staff during a visit to the Tayto Castle crisp factory in County Armagh, Northern Ireland AFP via Getty General election: On the campaign trail The Lib Dem leader eats a marshmallow during a visit to Free Rangers Nursery in Midsomer Norton, Somerset PA General election: On the campaign trail Nigel Farage visits a butcher's shop in Sutton-in-Ashfield Reuters General election: On the campaign trail SNP leader Nicola Sturgeon visits Blosson Tree children's nursery AFP via Getty General election: On the campaign trail Jeremy Corbyn laughs during a visit to the Scrap Creative Reuse Arts Project, Sunny Bank Mills Getty General election: On the campaign trail Prime Minister Boris Johnson hold Rosie the rabbit during a visit to a primary school while on the campaign trail in Taunton AFP via Getty General election: On the campaign trail Jo Swinson playing with children at the Battersea Arts Centre in Lavender Hill PA General election: On the campaign trail Farage addresses supporters at the Washington Central Hotel in Workington PA General election: On the campaign trail Jeremy Corbyn poses with Labour activists as they canvas in Govan, Glasgow PA General election: On the campaign trail Nicola Sturgeon during a visit to The Shed, a Climate Challenge community project at North Edinburgh Arts PA General election: On the campaign trail Prime Minister Boris Johnson meets six month old Willow Rose Anderson, at the Lych Gate Tavern in Wolverhampton PA General election: On the campaign trail Jo Swinson holds up a sack of barley during a visit to Crafty Maltsters Scotland Getty General election: On the campaign trail Jeremy Corbyn tries a scone in Bentley, Doncaster PA General election: On the campaign trail Nigel Farage takes a mouthful of homemade cheesecake during a stop at the Grimsby Seafood Village PA General election: On the campaign trail Boris Johnson hauling a consignment of frozen chocolate gateaux, during a visit to Iceland Foods HQ in Deeside PA General election: On the campaign trail Jo Swinson puts on a high visibility jacket during a visit to Sigma Pharmaceuticals, a family run pharmaceutical wholesaler in Watford AFP via Getty

Martin Hewitt, chair of the NPCC, said the intimidation of candidates in elections “has serious implications for individuals and for our democracy”.

“Strong and varied views are the mark of a healthy democracy, but these should not cross the line into criminal abuse, harassment or disorder,” he added.

“We’re not going to tell anyone to limit their campaigning or enthusiasm in any way – but we are taking precautionary steps ourselves and providing sensible advice to candidates.”

Election candidates were previously offered advice in meetings with local returning officers, while MPs can seek help from a parliamentary unit that was established after the murder of Jo Cox.

The NPCC told The Independent it was “stepping up” precautions in response to increased threats, and wanted to create a “level playing field” giving new candidates the same level of support as former MPs.

The body also hopes that the drive will increase the intelligence it receives on crimes against politicians, as senior officers are assigned to candidates in each area.

Mr Hewitt will be having briefings every morning leading up to the vote on 12 December and will give directions on how to respond to any emerging trends.

The intensified safety operation comes after an unprecedented increase in abuse and threats against politicians, which have been partly blamed for causing some MPs not to seek re-election.

Several people have been prosecuted for harassment, including a Brexiteer who threatened to “cut the f***ing throat” of pro-Remain politicians and called them “traitors”.

Anna Soubry, who was harassed by the pro-Brexit “yellow vests” before defecting from the Conservatives to lead Change UK, said holding an election in December was exacerbating safety risks.

Anna Soubry comments on police refusing to intervene during altercation with Brexiteer men outside Parliament

“It’s dark by 4.30pm and by the end of this campaign it will be dark even earlier,” she told The Independent. “All in all, it’s not a great time to hold an election.”

Ms Soubry said that while “robust exchanges” have always happened on the doorstep, online abuse was increasing security fears.

“It comes from left and right in a way that we’ve never seen before,” she added.

“It’s really sad that we are in this position where the police feel the need to issue this new advice because of the very real threats made to MPs. It’s a new phenomenon and it’s obviously hugely concerning.”

Dame Cressida Dick, the Metropolitan Police commissioner, has described the scale and ferocity of the attacks on MPs as “extraordinary”, saying “polarised opinion” on political and social issues was having an impact.

Several MPs have appealed for Boris Johnson to moderate his language and said they were experiencing an increase in personal abuse.

But the prime minister has defended his speeches and called suggestions of a link to threats to the safety of his fellow politicians “humbug”.

Ms Soubry said it was “absolutely shameful” that some senior politicians had not called out inflammatory language used by their peers.

“What’s happened is that Brexit lifted a stone and a lot of very unpleasant things have crawled out,” she added.

“They were always there, but my real concern is the level of debate and language used has dropped to a level we’ve never seen before.

A noose seen in the crowd at a ‘Brexit betrayal’ march in December 2018 (Angela Christofilou/The Independent)

“Senior politicians on all sides should have recognised that the language used has consequences for people’s safety. We need to reset the dial to do politics in a better and more decent way.”

At a press briefing in September, police officers revealed that reports of abuse against MPs spiked around debates over the Benn Act and the prorogation of parliament.

The NPCC lead for operations said: “Nobody, including MPs, should expect to experience abuse and harassment, nor their families or staff.”

“Sometimes the way things are said can be perceived as giving permission to people to act beyond the normal boundaries ... it does have an impact on people,” Chief Constable Charlie Hall added.

“We know some of that debate is quite strong but we ask people, when those debates take place, that they are respectful and mindful of the impact that’s being had on others.”

The Electoral Commission called for all parties to “campaign responsibly”.

“Robust political debate is part of a healthy democracy, but sometimes things can go too far. Intimidating and abusive behaviour have no place in our political system,” said chief executive Bob Posner.