Former Northern Ireland secretary Peter Mandelson has predicted that Labour will "seize the chance" to hold an early referendum on joining the euro.

In an FT article today, Mandelson writes: "If an opening is created during the course of this parliament, I believe he [Tony Blair] will wish to seize the chance and not wait for the opinion polls to turn in favour."

Mandelson also predicts that Gordon Brown will not block a referendum held in appropriate circumstances.

Following Europe minister Peter Hain's suggestion that Britain's membership of the European currency was inevitable, foreign secretary Jack Straw warned that people needed to "calm down" over the issue.

The euro's first business day was judged to be broadly successful, with European Commission officials describing themselves as "extremely satisfied" with the change over. With the logistical operation running smoothly, the euro rose strongly on the foreign exchange markets, with its biggest one day rise against sterling.

And the introduction of the single currency prompts a front page Mirror leader urging Tony Blair to "stop your embarrassing dithering" and get on with joining the euro. Britons are "whining about the end of the pound, kidding ourselves we are still some great empire, and ignoring the fact that we're rapidly becoming the continent's laughing stock" argues the paper.