David Cameron has claimed that Gordon Brown has "lost control" of the Scottish Labour Party after Wendy Alexander called for an immediate referendum on independence.

Speaking during prime minister's questions in the Commons on Wednesday, the Conservative leader called on Gordon Brown to say if he agreed with Alexander on whether the future of the Union should be put to a public vote.

However, the prime minister denied that the Scottish Labour leader had called for a referendum and pointed to the Calman Commission which had been set up to review the progress of devolution "before making any further decisions".

Cameron pointed to Tory gains in the local and London elections, after which the prime minister pledged to "listen and lead" and accused him of "losing touch with reality".

The Tory leader quoted Alexander as saying: "I don't fear the verdict of the Scottish people. Bring it on."

"What else could that possibly mean?" he asked.

"Does he agree with Wendy Alexander or not? It's not much leadership if no-one's really following him."

Brown said he believed that "all parties in the House" would "welcome the fact" that the Calman Commission is looking at the issues.

"When we review the progress of the Calman Commission, we can make further decisions," he said.

And he claimed that Alexander was pointing to the "hollowness" of the SNP who said they wanted independence immediately and now want to postpone a referendum until 2011.

"She was making it clear that what the SNP was doing was against their election manifesto," he said.

Cameron replied: "The one thing I think people thought about this prime minister was that he was quite a good political fixer and he's now lost control of the Scottish Labour Party. So no leadership on the Union."