Nigel Farage has quit Ukip over its appointment of far right figurehead Tommy Robinson as an adviser.

The former party leader announced the decision simultaneously on his LBC radio show and in a column for The Daily Telegraph.

"With a heavy heart, and after all my years of devotion to the party, I am leaving Ukip today," he wrote in the newspaper.

The party has "changed fundamentally" under the leadership of Gerard Batten, Mr Farage said, accusing the MEP of an "obsession" with Robinson and a "fixation" with Islam.

"I believe he is entirely unsuitable to be involved in any political party," Mr Farage wrote of Robinson. "The fact is that his entourage includes violent criminals and ex-BNP members.

"Many Ukip members - including Ukip’s NEC – urged that Robinson should not become an advisor to Batten. Sadly, these pleas fell on deaf ears."

Nigel Farage says Ukip's appointment of Tommy Robinson is 'dragging us in a shameful direction'

He added: "My heart sinks as I reflect on the idea that they may be seen by some as representative of the cause for which I have campaigned for so much of my adult life."

Robinson, whose real name is Stephen Yaxley-Lennon, is currently banned from becoming a member by party rules, but has been inciting his supporters to join Ukip so they can influence its policies.

The national executive committee (NEC) delayed a potential ballot on Robinson’s membership until after Brexit in March, but Mr Batten responded by making him an “adviser” on grooming gangs and prisons.

On Sunday, Mr Batten survived a vote of no confidence mounted by Mr Farage's supporters.

Tommy Robinson supporters protest outside the Old Bailey Show all 16 1 /16 Tommy Robinson supporters protest outside the Old Bailey Tommy Robinson supporters protest outside the Old Bailey A Tommy Robinson supporter in London after former English Defence League (EDL) leader Tommy Robinson left the Old Bailey where his contempt of court case was adjourned PA Tommy Robinson supporters protest outside the Old Bailey A Tommy Robinson supporter outside the Old Bailey in London where the former English Defence League (EDL) leader is accused of contempt of court PA Tommy Robinson supporters protest outside the Old Bailey Tommy Robinson supporters outside the Old Bailey in London before former English Defence League (EDL) leader Tommy Robinson arrives accused of contempt of court PA Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right figurehead Tommy Robinson demonstrate outside the Old Bailey Getty Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right figurehead Tommy Robinson demonstrate outside the Old Bailey Getty Tommy Robinson supporters protest outside the Old Bailey Supporters of former English Defence League (EDL) leader Tommy Robinson protest at the Old Bailey Courthouse EPA Tommy Robinson supporters protest outside the Old Bailey Supporters of former English Defence League leader Stephen Yaxley-Lennon, or 'Tommy Robinson', who was jailed for contempt of court in May and later released, wait for him to arrive at the Old Bailey to attend a court hearing Reuters Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right figurehead Tommy Robinson demonstrate outside the Old Bailey Getty Tommy Robinson supporters protest outside the Old Bailey Tommy Robinson arrives for his hearing at the Old Bailey Reuters Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right figurehead Tommy Robinson demonstrate outside the Old Bailey Getty Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right spokeseman Stephen Christopher Yaxley-Lennon, AKA Tommy Robinson, the former leader of the right-wing EDL (English Defence League) wave flags as they demonstrate outsise The Old Bailey AFP/Getty Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right figurehead Tommy Robinson demonstrate outside the Old Bailey EPA Tommy Robinson supporters protest outside the Old Bailey epa07050344 Supporters of former English Defence League (EDL) leader Tommy Robinson protest at the Old Bailey Courthouse in London, Britain, 27 September 2018. The far right figurehead whose real name is Stephen Yaxley-Lennon faces a rehearing after winning an appeal against a contempt of court finding last month. EPA/NEIL HALL NEIL HALL EPA Tommy Robinson supporters protest outside the Old Bailey Robinson gestures to supporters from inside the Old Bailey AFP/Getty Tommy Robinson supporters protest outside the Old Bailey Supporters of far-right spokeseman Stephen Christopher Yaxley-Lennon, AKA Tommy Robinson, the former leader of the right-wing EDL (English Defence League) demonstrate outside The Old Bailey, London's Central Criminal Court, in central London on September 27, 2018. (Photo by Daniel LEAL-OLIVAS / AFP)DANIEL LEAL-OLIVAS/AFP/Getty Images DANIEL LEAL-OLIVAS AFP/Getty Tommy Robinson supporters protest outside the Old Bailey epa07050343 Supporters of former English Defence League (EDL) leader Tommy Robinson protest at the Old Bailey Courthouse in London, Britain, 27 September 2018. The far right figurehead whose real name is Stephen Yaxley-Lennon faces a rehearing after winning an appeal against a contempt of court finding last month. EPA/NEIL HALL NEIL HALL EPA

“I would never have joined Ukip as it stands today, obsessed as it is with becoming a successor to the British National Party (BNP) and the English Defence League (EDL), Suzanne Evans, Ukip's deputy chair, said as she resigned following the vote.

Ms Evans accused Mr Batten of taking Ukip in a "perverse direction" and of "putting an increasingly hostile and vicious focus on attacking the Muslim community en masse”.

Robinson founded the EDL in 2009 but left four years later. The anti-Islam activist now styles himself as an “independent reporter” and has capitalised on a surge of publicity over his imprisonment earlier this year to forge political ties across Europe, the US and Australia.