Liam Fox has described the prime minister as a "serial betrayer of British interests".

The Conservative chairman launched his attack following confirmation that hundreds of thousands of non-British citizens living in the UK would be able to vote in any referendum on joining the euro.

"Tony Blair is shown as a serial betrayer of British interests as it becomes clear that foreign nationals can vote in a British referendum on the euro but British citizens are denied a say on the EU constitution," said Fox.

"The Electoral Commission's confirmation that a bill will allow foreign nations a say on British membership of the euro shows the level of Blair's contempt for the national interest of the British people.

"Never have we had a prime minister so contemptuous of our history and identity."

And the Tory chairman said the latest news was proof of the "undemocratic instinct" of "the most un-British government we have ever had".