Tony Blair has insisted that the economic arguments will win the day on whether the UK adopts the euro - and not celebrities or pop stars.

The prime minister was responding to the anti-euro campaign's proposed cinema advert featuring comedian Rik Mayall as Hitler welcoming the single currency.

It is a harmless comedy sketch for three seconds in a 90 second film

No campaign director George Eustice

As criticism mounted of the advert, Mr Blair declined to condemn the advert, saying "a joke is a joke", saying the best way to respond was to win the argument on the currency.

He added that the Save the Pound campaign seemed to be basing its efforts on an image of Europe half a century out of date.

The cinema advertisement was described as "offensive" by Liberal Democrat leader Charles Kennedy, and has been branded tasteless by leading British Jews.

Mayall out of his Hitler gear

They say the advert, due to be screened across Britain, is an insult to the memories of the Holocaust victims.

But the No campaign argues the celebrity advert is a bit of "harmless fun" in the bid to win people over to its arguments.

In the advert, Rik Mayall is seen dressed as Hitler saying: "Ein Volk, ein Reich, ein euro" - one people, one realm, one euro - in a reference to the Nazi slogan: "Ein Volk, ein Reich, ein Fuehrer".

The comedian then reappears saying in English: "Euro? Oh yes please."

'Desperate' campaign

The European Commission described the advert as "crass and offensive" and in "appallingly bad taste". A spokesman said it was "insulting" and "panders to xenophobia".

The Britain in Europe group denounced the advertisement as a "tasteless caricature."

Its views are shared by the chairman of the Holocaust Educational Trust, Labour peer Lord Janner.

He described the portrayal as "crass, distasteful and totally inappropriate".

Bob Geldof says no to the euro

"Those responsible should withdraw this offensive advert immediately," said Lord Janner.

Former European Commission vice-president and Tory cabinet minister, Lord Brittan of Spennithorne, also criticised the advert.

"This tasteless ad shows the underlying nastiness behind much of the No campaign as well as an element of desperation," he said.

But the No campaign director George Eustice denied the advert was offensive.

"It is a harmless comedy sketch for three seconds in a 90 second film," he said.

Rock star Bob Geldof, comedians Vic Reeves, Harry Enfield and John Sessions, chef Gordon Ramsay, as well as Labour MPs Diane Abbott and Kate Hoey are among those who appear in the video campaign.