Brexit campaigners are bracing themselves for another high profile defection after the Labour MP Khalid Mahmood revealed he is preparing to switch sides in the referendum campaign.

Mr Mahmood, a former board member of Vote Leave, is expected to follow the Tory MP Sarah Wollaston in confirming that he has changed their minds about Britain’s future in the EU.

Embarrassingly Mr Mahmood is expected to blame the "racist" undertones of the Brexit campaign for his decision saying Vote Leave has been "hijacked" by the issues of immigration and race.

Speaking to The Daily Telegraph Mr Mahmood said he was "disappointed" by Boris Johnson's comments about Barack Obama's father being from Kenya and by the focus on Turkish accession.

He also expressed concerns about Nigel Farage’s comments about migrants coming to the UK.

Asked if he is preparing to change his mind Mr Mahmood said: "Yes, I could be yes."

"The issue for me is the economy, but the debate has been hijacked by people to do with immigration and racism,” he said.

“When Boris Johnson talks about where Obama's father comes from, what's that got to do with anyone? Why do we need to talk about who his parents are? That disappointed a lot of people.

"Then there was the advert about passports and the campaign saying Turkey could join the EU - that 76million people are coming to the UK and there have been a number of other things they used in a fairly racist context.

"I find that fairly offensive.

"My motivation originally was looking at the economy and the Commonwealth."

What to believe about the EU referendum

The Independent revealed earlier this year that Mr Mahmood had resigned from the Vote Leave board and did not plan to play an active role in the campaign.

He said at the time he was more concerned about campaigning on other issues.