A specialist police unit set up to investigate threats against MPs following the murder of Jo Cox has received 53 complaints in its first six months.

Figures obtained through a Freedom of Information request reveal MPs reported hate messages, harassment and criminal damage. The majority of cases – 33 out of 53 – were for malicious communications including Twitter trolling.

There were 13 reports of theft, three of harassment and four of criminal damage, although it has not yet been disclosed how many resulted in charges.

The Met’s Police Parliamentary Liaison and Investigations team was set up after the shocking killing of Ms Cox by neo-Nazi Thomas Mair as she left her North Yorkshire constituency surgery last June.

An extra £640,000 was spent bolstering security for MPs after several other female politicians revealed they had received rape and death threats online.

Male MPs have previously been targeted, including Labour’s Stephen Timms, who was stabbed in 2010 at his constituency surgery in east London.

A survey of female MPs earlier this year revealed more than half had been abused online, with many left feeling more vulnerable following the murder of their colleague. A third of the 73 who responded said they had considered giving up their jobs because of the abuse they received.

Internet troll John Nimmo, 28, from South Shields, was jailed for 27 months in February after making anti-Semitic threats to Liverpool Labour MP Luciana Berger. He had previously been jailed for threats he made to feminist campaigner Caroline Criardo-Perez and London Labour MP Stella Creasy.

Birmingham Yardley MP Jess Phillips revealed last year she called in a locksmith to bolster security in her home after she was sent a mocked-up picture of her death on Twitter.

Labour’s York MP Rachael Maskell was targeted by online trolls around the time of Ms Cox’s murder when she was sent an image of a severed head among other “very nasty” emails.

Speaking out about the abuse, Ms Maskell called on social media companies to do more to remove abusive and threatening posts and to help trace those responsible.

She said: “Freedom of speech is so important - it is what we value across our country - but the abuse I received online went way beyond that.

”We need to make sure we have a zero tolerance to abusive behaviour online.“

Armed police guard the corridors in Westminster but some politicians are taking extra precautions, such as changing where they hold their constituency surgeries.

Liberal Democrat MP Tom Brake, who has just had extra security installed at his home, said he received threatening emails around the time of the EU referendum advising him to “think carefully” about how to vote for the sake of his family.

“Most MPs spend most of our time in Parliament where we are protected, but our families very often are in the constituency, and therefore anyone who is even alluding to the vulnerability of our families is someone who causes a lot of disquiet.”

The SNP’s Dr Lisa Cameron said as soon as she was elected to Parliament in 2015, she became the target of abuse, both online and in the post directed towards her and her family.

Jo Cox tributes - in pictures Show all 20 1 /20 Jo Cox tributes - in pictures Jo Cox tributes - in pictures Floral tributes and candles are placed by a picture of slain Labour MP Jo Cox at a vigil in Parliament square in London AFP Jo Cox tributes - in pictures Tributes to Labour Party MP Jo Cox are placed on her houseboat in Wapping in London REUTERS Jo Cox tributes - in pictures The Union flag at half-mast on top of Portcullis House in London after Labour MP Jo Cox was shot and stabbed to death PA Jo Cox tributes - in pictures Labour leader Jeremy Corbyn (2R) and deputy leader Tom Watson (L) light candles as they attend a vigil to slain Labour MP Jo Cox in Parliament square in London AFP/Getty Images Jo Cox tributes - in pictures Labour Party leader Jeremy Corbyn and deputy leader Tom Watson (rear) arrive to leave tributes at Parliament Square PA Jo Cox tributes - in pictures People leave St Peter's Church after a vigil in memory of Jo Cox REUTERS Jo Cox tributes - in pictures Flowers left at Parliament Square opposite the Palace of Westminste, following the death of Labour MP Jo Cox PA Jo Cox tributes - in pictures People react as they look at tributes left for Labour Member of Parliament Jo Cox in Parliament Square, London REUTERS Jo Cox tributes - in pictures A man writes a message at Parliament Square PA Jo Cox tributes - in pictures People stop to look at tributes left at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman arrives to lay flowers at a statue to Joseph Priestly in Birstall near to the scene where Labour MP Jo Cox was shot AFP/Getty Images Jo Cox tributes - in pictures Tributes at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman places candles in tribute to Labour Party MP Jo Cox REUTERS Jo Cox tributes - in pictures A member of the public signs a memorial for British MP Jo Cox in Parliament Square, London EPA Jo Cox tributes - in pictures People sign messages of condolence for MP Jo Cox during a vigil in Parliament Square in London Getty Images Jo Cox tributes - in pictures Flags at half mast outside Scottish Parliament in Edinburgh, after Labour MP Jo Cox was shot and stabbed to death in the street outside her constituency advice surgery in Birstall PA Jo Cox tributes - in pictures People arrive in Market Square with floral tributes after the death of Jo Co Getty Images Jo Cox tributes - in pictures Floral tributes are placed in Market Square next to the statue of Joseph Priestley following the death of Jo Cox Getty Images Jo Cox tributes - in pictures Floral tributes are brought to the scene after the death of Jo Cox Getty Images Jo Cox tributes - in pictures A police officer carries bunches of flowers at the scene of the shooting of Labour MP Jo Cox in Birstall REUTERS

“It’s something I think you can’t treat too lightly. The security measures are certainly a step in the right direction.