Mr Kaczynski has been a long-time critic of the Treaty, playing on fears that it would force Roman Catholic Poland to accept homosexual marriages and more liberal laws on abortion.

He said he was happy to see the EU carry on as it was rather than agree to a new rulebook.

Mr Kaczynski added: “It’s not right to say, ‘If there is no Treaty, there is no EU’.

“The EU worked, is working and will work. It isn’t ideal, but a structure this complicated couldn’t be.”

It emerged yesterday that he could be forced to sign anyway after Poland’s prime minister, Donald Tusk,  backed the Treaty.

But Mr Kaczynski’s comments have added to the growing rebellion after Czech president Vaclav Klaus vowed not to sign.

Sweden’s parliament may also reject the Treaty.

France is threatening to retaliate by blocking Croatia’s entry to the EU.

And Mr Sarkozy is backing efforts to force the Irish to hold a second referendum.

Asked this week if Ireland should vote again, he said tellingly: “I don’t want to say it like that because it would give the impression of forcing their hand.”

If the Irish refuse or vote no again, they could be told to quit the EU. Nineteen countries, including Britain, have approved the Treaty.

Labour reneged on a manifesto pledge to hold a referendum on the new European Constitution when it was replaced by the virtually identical Lisbon Treaty.