POLL: Do you agree with UKIP plans to ban the burka?

Mr Nuttall has sparked widespread controversy with his proposal to outlaw the full-face veil worn by some Muslim women, as well as banning sharia law and forcing girls at risk of female genital mutilation (FGM) to face regular medical checks.

Announcing that he was resigning as the party's foreign and Commonwealth affairs spokesman, West Midlands MEP James Carver described the policy as "incompatible" with his desire to represent all of his constituents and to seek a global perspective for the United Kingdom.

Mr Nuttall's so-called integration strategy had already been panned by former UKIP donor Arron Banks, who accused him of going to "war" with Muslim communities.

But deputy leader Peter Whittle defended the strategy, saying: "The burka is not something in the Koran, it's not specified by the Koran, it's a cultural practice, FGM is a cultural practice."

Mr Carver said he "strongly disagreed" with a policy he regarded as "misguided".

"I would be one of the first to condemn a ban on wearing a crucifix as an infringement of liberty," said Mr Carver.

"No-one has the right to dictate what people should wear.

"When facial identification is necessary, such as at passport controls, or in a bank, then it is perfectly reasonable to order the removal of veils - as is the practice - but in a free and liberal society, people have a right to their religious beliefs, and to dress as they see fit."

Mr Carver said he stepped down as party spokesman "with deep regret", but added: "I feel this policy undermines my desire to represent all communities within the West Midlands, including the many British Muslims who, I know from first-hand experience, voted to leave the EU in last year's referendum.

"I have consistently spoken of my desire for a truly global perspective for the United Kingdom, outside of the European Union, and I see this policy as being incompatible with that aim."

Earlier, Mr Whittle had told BBC Radio 4's Today programme: "We have talked about these issues in UKIP for many years - 2010 we actually had this in our manifesto, that we should ban face coverings - not, for example the headscarf, not those sorts of things at all, just purely the face covering, because we believe that is a literal barrier to integration in our society.

"We are actually in this country rather behind the curve on this, because even the biggest party in the EU has called for an EU-wide ban on this."

But UKIP was strongly condemned by the Muslim Council of Britain's secretary general Harun Khan.

In a speech to a Muslim leadership dinner, Mr Khan was due to say: "It is deeply regrettable that the UK Independence Party is singling out Muslims in the most negative terms.

"This is not leadership. And it is certainly not becoming of a party seeking to represent British people.

"Together with fellow Britons, Muslims will be looking for true leadership that unites our country during this time of uncertain transition and seek to represent all British people, and certainly not scapegoat some.

"Bigots must not be allowed to set the terms of the debate."

Meanwhile, Mr Whittle said Mr Nuttall "probably will" stand in the June 8 General Election, after the leader dodged the question at an event on Monday.