London - Tony Blair believes the case for joining the euro is "overwhelming", according to the latest in a series of leaked Downing Street memos published last night.
And he intends to tackle the Tories "head-on" on the issue to avoid accusations of weakness.
In the memo reproduced in the Sun and the Times, the Prime Minister says the government cannot avoid the debate on the single currency.
He writes: "Either we expose the Tories' posturing for what it is: a defeat of our national interest, or we just look weak".