The fight for Britain's future in the European Union was set to formally kick off on Monday with Prime Minister David Cameron presenting to parliament the reform measures he won during last week's negotiations in Brussels.
Cameron says the concessions give Britain a "special status" within the EU.
London Mayor Boris Johnson announced he will support Britain leaving the Union, a move known as "Brexit." In addition to being a fellow member of the Conservative Party, Johnson also has a national reputation and is seen as a potential political rival to Cameron.
Second, at least five members of Cameron's own cabinet have come out in favor of leaving the EU. While not entirely unexpected, it nonetheless is a blow to the prime minister.
And finally, reacting to the wave of opposition to EU membership negatively, the pound plunged against major currencies, including a 2.1 percent dive to $1.41 on Monday.
London mayor slams EU
In an opinion piece in Britain's largest right-wing broadsheet, the Daily Telegraph, Johnson said the EU project had "morphed and grown in such a way as to be unrecognizable" and insisted there was nothing xenophobic about opting out.
"We are seeing a slow and invisible process of legal colonization, as the EU infiltrates just about every area of public policy," he wrote.
He called the referendum a once-in-a-lifetime opportunity to alter Britain's relationship with Europe.
"There is only one way to get the change we need, and that is to vote to go, because all EU history shows that they only really listen to a population when it says No."
A rocky relationship
The concessions Cameron wrung from Brussels last week includes an explicit exemption from the founding goal of an "ever closer union," concessions on the welfare rights of migrant workers and safeguards for London as a financial center.
A public referendum is scheduled for June 23.
Britain's relationship with the EU has long been strained. It joined the block in 1973, when it was known as the European Economic Community (EEC). Subsequently Britain has opted out of integral EU projects such as the euro currency and the passport-free travel zone known as Schengen.
A public opinion poll released Sunday, the first since the Brussels deal, found 48 percent of Britons want to remain in the EU, 33 percent want to leave and 19 percent are undecided.
"Yes, of course if Britain were to leave the EU that might give you a feeling of sovereignty," Cameron said, "but you've got to ask yourself 'is it real?'"
bik/rc (AFP, AP, Reuters)