* Johnson says Britain should have an EU referendum
* Says Britain slipping towards EU exit
* Adds to pressure on Prime Minister Cameron over Europe
* Euro will limp on then blow up, mayor says
* But says Britain should stay in EU single market
LONDON, Dec 4 (Reuters) - London Mayor Boris Johnson heaped
pressure on Prime Minister David Cameron on Tuesday by calling
for a referendum on a deeply pared back British membership of
the European Union.
Johnson, speaking at a Thomson Reuters Newsmaker event, said
the euro was a calamitous project and that Britain should
negotiate a new treaty to prevent its slide out of the world's
biggest economic area.
"Boil it to down to the single market, that's the great
achievement of the European Union, I think we could easily scrap
the social chapter, the fisheries policy," Johnson, a
Conservative party member seen as a potential rival to Cameron,
said in a speech.
"That is a renegotiated Treaty we could and should put to
the vote of the British people.
"It is high time that we had a referendum, and it would be a
very simple question. Do you want to stay in the EU single
market - yes or no?"
Johnson sidestepped three questions on whether he would like
to be a future prime minister but he has set a high bar for
Cameron. Negotiating such a new deal with Europe would be
extremely difficult with EU allies unlikely to approve such a
radical treaty change.
"There will be a huge barrage from foreign legations saying
'this is not on the table, there is no way we'll accept this',"
said Johnson, a formidable campaigner whose messy mop of
platinum blond hair makes him instantly recognisable.
"The choice is going to be very simple: it's between staying
in on our terms or getting out," he told an audience of
investors and bankers.
Dropping out of the European Union could isolate the world's
sixth largest economy and bankers warn that such a dramatic move
would sap the power of the City of London, Europe's dominant
financial centre.
But the turmoil of the euro zone crisis and the prospect of
the currency bloc forming a closer political union that London
will not join have convinced many within the ruling Conservative
party and beyond that they must seek a new deal with Europe.
The issue, which has ripped previous Conservative
administrations apart, has shot to the top of the political
agenda with anti-EU party lawmakers pushing for a looser
relationship with the 27-nation bloc -- or even leaving
altogether.
BRIXIT?
Cameron, who is due to make a definitive speech on Britain's
place in Europe in coming months, has called for repatriating
powers before holding a referendum on the new settlement, though
he has given no timeframe for when a vote could be held.
He also has to cater for governing coalition partners the
Liberal Democrats who vehemently oppose looser ties with the EU.
Johnson said the best way to avoid a slide out of Europe was
his proposal.
"It's a deliverable deal," Johnson, ubiquitously known as
Boris across Britain, told Reuters after the speech.
"We're on the glide path to exit at the moment. That's
what's happening. What I'm really advocating is a way of getting
the best of both worlds, a way of keeping us in ... the valuable
thing, a gigantic free trade area."
Johnson, who has repeatedly upstaged Cameron at events such
as the Olympics, said Britain should look to have a similar
relationship with the EU as those enjoyed by Norway and
Switzerland.
"Indeed, if that were the relationship then there is every
chance that we would be joined in that outer tier by Norway and
Switzerland, since both those countries are feeling increasingly
frustrated by their lack of influence."
Asked if he would campaign to keep Britain within the
European Union if it renegotiated its treaty to be based around
the single market, the mayor said: "Yes."
But when pressed on timing, he said the government would be
very unlikely to hold such a referendum until after the next
election, which is due in May 2015.
'CALAMITOUS PROJECT'
Johnson cast the euro as a sinking project reliant on German
capital that was sowing social and political chaos across Europe
as the crisis engulfs Greece, Spain, Portugal and even France.
He cast scorn on France's central bank governor, Christian
Noyer, who said that the City of London should no longer be the
euro zone's main financial centre.
"I see no reason, with great respect to Mr Noyer, whose name
I think means to drown, from memory, why trade in the euro
shouldn't continue to be dominated by London," said Johnson, who
said London accounted for 40 percent of euro trade.
He said the euro area would limp on with sclerotic growth
before possibly blowing up at some point.
"The euro is a calamitous project, it will limp on with
sclerotic growth rates," Johnson said. "It will eventually blow
up but I wouldn't care to bet when."
Johnson's rhetoric on Europe and the highest approval
ratings among Conservative politicians has fuelled speculation
that he has his eye on Britain's top job.
A former correspondent for the right-leaning Daily Telegraph
in Brussels, Johnson, 48, has dismissed as "complete cloud
cuckoo land" speculation that he might seek election to
parliament during his mayoral term, which finishes in 2016.
But does Boris want to be prime minister?
"As Clint Eastwood says in one of his, I think it was "Dirty
Harry", a man's got to know his limitations. Being mayor of the
greatest city on earth is a fantastic thing to do," he said.