A Bradford MP may not be allowed back into the Liberal Democrat party when his suspension ends, Nick Clegg hinted yesterday.

Quizzed by the T&A at Westminster, the Lib Dem leader twice refused to say whether he expected to reach an agreement with the exiled Bradford East MP, David Ward. Instead, Mr Clegg took a hardline stance – insisting Mr Ward must never again appear to question the right of the state of Israel to exist.

And he revealed his frustration about the long-running row, when he said he had discussed it with the MP “until I am blue in the face”.

Mr Clegg said: “What I found totally unacceptable – and still find unacceptable – was his suggestion that any Liberal Democrat should raise questions about the right of Israel to exist as a state. “I believe and my party believes – and David Ward is a representative of the Liberal Democrats – in a two-state solution.It’s not consistent with our values and our policy to start raising questions about the existence of the state of Israel. That’s why I took the unprecedented step, after due process, to suspend the whip – the first time I have done that to a Lib Dem MP.”

Asked if an agreement would be reached, Mr Clegg said only: “I have set out a very clear position on this and that’s what I expect Liberal Democrat MPs to abide by.”

The comments cast doubt over whether Mr Ward’s suspension from the parliamentary party will end – as originally planned – on September 13.

The whip was withdrawn after Mr Ward sent a tweet reading “Am I wrong or are am I right? At long last the #Zionists are losing the battle – how long can the #apartheid State of #Israel last?”

In a stern letter, chief whip Alistair Carmichael said the MP had broken an undertaking to use language about Israel that was “proportionate and precise”. But Mr Ward insisted he had not questioned whether Israel should exist, only stating his belief that it could not survive in its current “apartheid” form. And, yesterday, he again vowed he would not be silenced, saying: “That’s what I believe – that the apartheid state of Israel cannot last indefinitely. I would be a liar if I didn’t say that. But this is not my problem. It’s a problem for the party and it’s up to them to sort it out.”

Mr Ward also made a fresh criticism of the Lib Dem leadership, saying: “The chief whip believes I am courting the Muslim vote. But that’s damned insulting both to Muslims and the white community I represent in Bradford, who regularly come up to me and offer their support.”

That suggestion is embarrassing for Mr Clegg, who insists Mr Ward is not prevented from making honestly-held criticisms of Israel and the suffering of the Palestinians. The deputy prime minister said, yesterday: “I have stressed that to David Ward – until I am blue in the face.”