Mr Anderson was suspended at the weekend after he refused to apologise for claiming "Islamists" had got "control" over London and that Mr Khan had "given our capital city away to his mates".

Mr Anderson's comments prompted a backlash from across the political divide, including from Tory peer Baroness Warsi who said she was "really disturbed by where the Conservative Party has gone" and that "anti-Muslim racism is being used as an electoral campaign tool".

Asked what Mr Anderson needed to say to be welcomed back, Transport Secretary Mark Harper told Kay Burley on Sky News that the former deputy party chair should "reflect on what he said" and "retract those comments and apologise".

I'm not going to tell the chief whip how to do his job, that's for him," he said.

"He's contributed a lot in the past. I'd like to see him be able to contribute to the Conservative Party in the future."

"I'd like to see him be able to contribute to the Conservative Party in the future."

While a number of senior Tories have criticised Mr Anderson for his comments, Mr Harper was the second cabinet minister to refuse to say whether the remarks were "racist".

Yesterday Mr Dowden backed the decision to suspend the Ashfield MP but refused to say whether he was racist.

Asked by Sir Trevor Philips whether the suspension of Mr Anderson meant the party regarded him as "racist" - or suspected him of being so - Mr Dowden twice refused to address the question and repeated that the Ashfield MP had used "the wrong words".

And this morning, Mr Harper repeatedly declined to say whether Mr Anderson's remarks were racist but said they were "untrue" and "wrong".

"Well it was wrong, and I'm not going to get into arguing about the rights and wrongs of what he said.

"Wrong is a very strong word in my book."

Mr Harper also rejected the assertion made by Tory peer Sayeeda Warsi yesterday that there is a hierarchy of racism within the party, and anti-Muslim racism is being used as an electoral campaign tool.

He said: "I don't agree with that. And the fact that we took such robust action so quickly against what Lee Anderson said, I think, rather shows exactly why she's wrong."