HUMZA Yousaf has called for David Cameron to rule out any post-election deal with Ukip after the party’s only Scottish MEP David Coburn compared the government minister to convicted terrorist Abu Hamza.

Despite politicians, religious leaders and equality campaigners across the political spectrum calling on Coburn to resign, Ukip have appeared to back their MEP, the same day Farage has proposed a coalition with the Conservatives.

Chancellor George Osborne repeatedly refused to rule out a coalition with Ukip after May’s election.

Speaking about a television debate he was set to appear in, Coburn said: “Humza Yousaf, or as I call him, Abu Hamza, didn’t seem to turn up.”

The party originally claimed the comment comparing Scotland’s only Muslim government minister to the terrorist was made

“in jest”.

The line was altered later in the day, however, as a Ukip Scotland spokesperson said it was simply a “slip of the tongue”, adding that “Humza really needs to develop a sense of humour and a thicker skin if he is going to be a politician.”

In his letter to the Prime Minister, MSP Yousaf states: “As a political party, Ukip have crossed the line of common decency and stepped into the murky waters of racism, bigotry and religious hatred, where they are now firmly entrenched.

“It is simply inconceivable that any mainstream political party could even contemplate doing any sort of post-election deal with them. There are hundreds of examples of such prejudiced slurs against minorities, faith groups, women and many others.”