Almost half of UKIP members think MI5 is trying to destroy their party, according to a new poll.

The YouGov survey found 46 per cent of members agreed with the statement “Intelligence services like MI5 have been working to undermine UKIP”. The poll echoes an earlier finding that almost a third of Ukip supporters believed MI5 was involved in a plot to rig the EU referendum result.

Other conspiracy theories are also popular among party activists. More than half (55 per cent) think some UKIP members have been planted by Conservative strategists to undermine the party, while 40 per cent believe the EU referendum was the subject of electoral fraud, with officials rubbing out and changing votes.

Almost nine in 10 (89 per cent) believe the media is being deliberately biased in its coverage of their party.

The survey of 1,003 Ukip members found the majority were former Conservative voters, with 66 per cent having voted for the Tories at a past general election, while almost a quarter have previously voted for Labour.

Surprisingly, almost one in seven Ukip members had previously voted for the Liberal Democrats or the Green Party.

The biggest issues of concern for Ukip members – immigration, Brexit, the economy and health – match those of the general public, but they are much more likely to be concerned about immigration and Brexit. Eighty-one per cent of the party’s members believe immigration is one of the most important issues facing the country, while 76 per cent believe the same is true of Britain leaving the EU.

Joe Twyman, head of political and social research at YouGov, told The Independent he was not surprirsed at the findings.

He said: “This really highlights the degree to which distrust of the establishment permeates the Ukip membership. If you’re suspicious of the establishment then you might think it possible that these things are happening.”

“[There is] an idea they are an anti-establishment party and therefore the establishment is going to take steps to act against them.”

He said conspiracy theories were also present among supporters of mainstream political parties but added: “We’ve certainly seen a larger support for these types of ideas amongst the members and the supporters of Ukip and the Scottish Nationalists.”

It comes as Ukip attempts to recover from a catalogue of difficulties that have plagued the party in recent works. Its leader, Diane James, resigned after just 18 days in the role, days before a public row between MEPs Steven Woolfe and Mike Hookem hit headlines after Mr Woolfe ended up in hospital alleging he had been punched by his colleague.

Mr Woolfe, the favourite to take over from Ms James, then resigned from the party after calling it “ungovernable” and saying he no longer knew what it stood for.

Key Faces of UKIP Show all 11 1 /11 Key Faces of UKIP Key Faces of UKIP Nigel Farage Getty Key Faces of UKIP United Kingdom Independence Party (UKIP) Migration spokesman Steven Woolfe addresses supporters and media personnel in central London Getty Key Faces of UKIP Robert Kilroy-Silk, former television presenter and newly elected member of the European Parliament for the UK Independence Party (UKIP), shows a placard against the European Constitution in front of the Houses of Parliament Getty Key Faces of UKIP Mark Reckless, Director of Policy Development addresses party members during the UK Independence Party annual conference at Doncaster Racecourse Getty Key Faces of UKIP Gerard Batten MEP poses with protesters outside parliament Creative Commons Key Faces of UKIP Diane James gives an address at the UKIP Autumn Conference in Bournemouth Getty Key Faces of UKIP Douglas Carswell MP speaks to party members and supporters during the UK Independence Party annual conference Getty Key Faces of UKIP Suzanne Evans, Deputy Party Chairman of UK Independence Party (UKIP) speaks during the launch of UKIP's election manifesto Getty Key Faces of UKIP Peter Whittle, the UK Independence Party Member of the London Assembly, is interviewed in central London Getty Key Faces of UKIP MEP Mike Hookem during a visit to Concept Metal Products & Co Ltd Getty Key Faces of UKIP Paul Nuttall, Deputy Leader of the UK Independence Party speaks at a Say NO, Believe in Britain debate at Carn Brea Leisure Centre in Pool near Redruthon Getty

In the poll, which was conducted before Mr Woolfe’s resignation, party members expressed their support for his leadership bid. Thirty-seven per cent would like to see the MEP lead the party, while 31 per cent want interim leader Nigel Farage to stay on permanently, despite him having only resigned from the post in July. The other candidates, including Suzanne Evans, trail some way behind.

Nominations in the party’s latest leadership contest close on 31 October, with the winner announced on 28 November. Frontrunners include Ms Evans, MEP Paul Nuttall and Raheem Kassam, a former aide to Nigel Farage.