Tony Blair has been pitched back onto the defensive over the war with Yugoslavia amid growing signs of deep divisions within Nato.

He was forced to deny claims that President Clinton was opposed to the use of ground troops.

And he attempted to play down comments by German Chancellor Gerhard Schröder that he would never commit land forces to the conflict.

Challenged over the rifts by Tory leader William Hague during question time, the prime minister insisted there was "absolutely no difference" between him and the US President.

He even went on to heap praise on his ally, declaring: "I know the President well. I know that he will always do the right thing by America and by the world and he is as committed to this campaign as anybody else."

He also denied that Chancellor Schröder's remarks amounted to a split in the alliance.

But the prime minister, while not yet a lone voice in Nato, is starting to look like the leader most committed to the action.

Moral issue

He has previously spoken of it as a "moral" issue and his visits to the region seem to have strengthened his resolve to see the action through to the bitter end.

The problem is, there seems to be growing uncertainty about exactly what that bitter end will be and whether all the allies agree on how it should be reached.

There is little doubt that President Clinton is looking for a credible way out of the conflict and, despite his personal expressions of support, does not have the backing of either the voters or the Senate for the use of ground troops.

Schröder: No ground troops

Things are worse in Europe where Germany, Italy, Greece and Hungary are implacably opposed to the use of ground forces and even France and Turkey are in two minds.

Meanwhile the calls for a temporary halt to the bombing to allow the diplomatic route to be further explored are growing.

There were even confused signals from the government that Mr Blair might be prepared to accept this as the best way out of the impasse.

He used question time to flatly deny such suggestions, declaring there would be "no compromise".

Liberal Democrat leader Paddy Ashdown summed up the crisis facing the government when he demanded: "Isn't the true situation in Kosovo simply this. Only if Nato is prepared to use ground troops can we be sure of victory.

No compromise

"If Nato is not prepared to use ground troops then it may have to be satisfied with compromise."

The prime minister dismissed the suggestion, saying there was : "no question of compromise in our basic demands.

"We have said we keep all options under review but there can't be any compromise on our demands.

"In the end the Kosovar Albanians have got to feel free and safe to go back. They cannot do that unless the international military force is credible and unless Milosevic's troops are withdrawn," he said.

And, for the umpteenth time, he insisted that the air strikes would eventually work.

But there is now a growing sense that this conflict is moving towards its climax, and there are real fears that the alliance is deeply split over how to escape it.

If air strikes do not work, and there is only a limited amount of time before that calculation will have to be made, there is a real possibility that Mr Blair will end up a lone voice when it comes to the hugely difficult decision about land forces.