Britain First, the far-right political party responsible for vigilante “invasions” of mosques and a campaign against the “Islamification” of Britain, has told its supporters to help deliver “major Ukip gains” at the general election.

Letters and leaflets currently being distributed by Britain First, a group formed by former British National Party members, effectively endorse Nigel Farage’s party.

The literature obtained by The Independent – carrying the signature of Britain First’s leader, Paul Golding – says its controversial activities “in the Muslim ghettoes” will combine with “major Ukip gains” to turn the election into a “game changer”. Claiming 2015 will be “the year of Britain First and Ukip”, the group forecasts a “resurgence of right-wing patriotism in Britain”.

Mr Farage has previously tried to distance himself from support and associations offered to Ukip from the extreme right, both in the UK and from hard-right groups inside the European Parliament. Britain First has said it “understands” how Ukip must play the “political game”, and told its supporters to “ignore Ukip’s necessary political bluster”.

Election Analysis: The Key Voters Show all 6 1 /6 Election Analysis: The Key Voters Election Analysis: The Key Voters Settled Silvers These are the comfortably-off over-60s, still in work or drawing a decent pension – or both – who are enjoying their entitlements such as the Winter Fuel Allowance, free bus passes and free TV licence. They are worried about immigration and Europe. Both the Conservatives – who are pledging to keep benefits for wealthier pensioners – and Ukip want their votes Micha Theiner Election Analysis: The Key Voters Squeezed Semis Slightly older than the Harassed Hipsters, they are the second key group for Labour’s family-focused election strategy. They are married couples on low to middle incomes who own unpretentious semi-detached homes in suburban areas. In 2001, these were the Pebbledash People sought by the Conservatives. Now the pebbledash is gone and a modest conservatory has been built at the back Micha Theiner Election Analysis: The Key Voters Aldi Woman In 1997 and 2001 she was Worcester Woman – a middle-class Middle Englander shopping at Marks & Spencer and Waitrose. Today, the age of austerity means she still goes to Waitrose for her basic food shop but cannily switches to Aldi for her luxury bargains such as Parma ham and prosecco. Identified by Caroline Flint, she is a key target of both Labour and the Conservatives Micha Theiner Election Analysis: The Key Voters Glass Ceiling Woman In her thirties or forties, she has an established career under her belt, perhaps in the “marzipan layer” – one position below the still male-dominated senior executive level. She is now, according to Nick Clegg, forced into making the “heart-breaking choice” between staying at home to bring up her children and going to work and forking out for high-cost, round-the-clock childcare Election Analysis: The Key Voters Harassed Hipsters One of the two key groups identified by Labour as crucial to hand Ed Miliband the keys to Downing Street. Well-paid professional couples, often with children, they live in diverse urban and metropolitan areas rather than the suburbs. More comfortably off than most swing voters, they are time poor – struggling to balance raising a young family with busy work schedules Micha Theiner Election Analysis: The Key Voters Neo-Greens These are mainly first-time voters, though some are in their twenties – students and digital-age generation renters helping to fuel the “Green Surge”. Idealists, but with no tribal loyalty to any party, they are anti-austerity, middle class, living in urban areas. Despite studying at university or recently graduated, they are struggling to find decent jobs and want cheaper housing and a higher minimum wage Micha Theiner

At last year’s Rochester by-election – won by Mark Reckless, the former Conservative who defected to Ukip – campaign literature distributed by the group proclaimed: “Ukip at the ballot box, Britain First on the streets – a winning combination.”

Ukip recently abandoned strict targets and caps on immigration numbers as part of its central policy to “get back control over Britain’s borders.” Britain First wants “assisted repatriation”, a halt to further immigration, and the deportation of all asylum seekers. It also wants all foreign criminals to be deported without recourse to the law courts.

Although the Ukip leader cannot control who offers his party support, the endorsement from a group as extreme and controversial as Britain First will nevertheless be regarded as unwelcome and potentially damaging.

Last year the group, which has its origins in Ulster loyalism and anti-abortion campaigns, conducted “Christian patrols” in parts of East London where Muslim residents would have been offended by the action. The group said the “patrols” were a direct response to similar Muslim groups who, it was claimed, wanted Sharia Law enforced in some boroughs. Britain First activists were seen outside mosques holding banners announcing: “We are the British resistance.”

The group were also responsible for raids on mosques in Glasgow, Bradford, Luton and London. Bibles were offered to attending Muslim worshippers. During the 2014 European elections, Britain First put up candidates in Wales and Scotland. The party received just over 20,000 votes. In England it encouraged its supporters to vote for Ukip or the English Democrats. However, the party leader’s comment that 2015 was the year of “Britain First and Ukip” suggests that Mr Farage is now regarded as the preferred choice.