London Mayor backs Brexit, but British big business is less convinced

London mayor Boris Johnson has thrown his weight behind the campaign for the UK to leave the EU, while a group of big businesses has done the opposite. But the motives of both have been cast into doubt.

Debate over whether the United Kingdom should remain in the European Union (EU) – a subject likely to dominate British politics until the matter is decided in June – has burst into life since Prime Minister David Cameron announced Saturday the date of the referendum.

The mayor of London, Boris Johnson, possibly the most colorful and well-liked personality in British politics, declared his support Sunday for leaving the EU, though skeptics suggest this move may have more to do with his desire to become prime minister than any desire for his country to break away.

In a boost to the "In" campaign, a group of heavyweight British businesses published a letter the following day, extolling the benefits of staying in the EU – although skeptics, once again, cast doubt on their motives, pointing to all the businesses that chose not to sign.

“This is a moment to be brave, to reach out – not to hug the skirts of Nurse in Brussels, and refer all decisions to someone else,” wrote Mr. Johnson in The Telegraph.

We have given so much to the world, in ideas and culture, but the most valuable British export and the one for which we are most famous is the one that is now increasingly in question: parliamentary democracy – the way the people express their power.

This is a once-in-a-lifetime chance to vote for real change in Britain’s relations with Europe. This is the only opportunity we will ever have to show that we care about self-rule. A vote to Remain will be taken in Brussels as a green light for more federalism, and for the erosion of democracy.

Many commentators say that, given Johnson’s fame and stature, his sudden announcement could provide a significant surge to the campaign urging voters to break away from the EU.

Indeed, Prime Minister Cameron, who supports Britain's staying in Europe, took to mocking and ridiculing Johnson’s stance during parliamentary debate Monday, taking particular aim at the mayor’s apparent suggestion that negotiations on UK membership of the EU could be rejoined after a British vote to leave the union.

But the prime minister also hinted at his skepticism of Johnson’s motives:

“I am not standing for re-election. I have no other agenda than what is best for our country. I am standing here today telling you what I think. My responsibility as prime minister is to speak plainly about what I believe is right for our country.”

And Cameron is not the only one who wonders what Johnson is really up to. Long touted as a possible successor to the prime minister, Johnson’s star has lately been waning, as Chancellor George Osborne has appeared to cement his position as something of a prime minister in-waiting.

But Mr. Osborne has already lent his support to the "In" campaign, meaning that should the UK vote to leave the EU, leadership of the Conservative party would now likely fall neatly into Johnson’s lap. And even if the country remains in the European Union, Johnson's prospects would not be shattered.

“But shamelessly self-interested and probably contrary to his real views on the EU though it is, the mayor’s move is perhaps not entirely disingenuous,” notes The Economist. “He has always insisted that his decision would turn on his concerns that EU membership is incompatible with British sovereignty. Expect him to concentrate on this objection in the coming days.”

And then there’s the letter from British businesses, stating that leaving the EU would “put the economy at risk,” lending credence to the opposite stance, that the UK would be better off remaining in the EU.

But there are plenty of businesses that chose not to lend their names to the letter, for various reasons, and, as the Financial Times reports, the letter itself was also arranged by the prime minister’s own business relations advisor, something critics have pounced on.

“The PM has admitted using taxpayers' money and applying pressure on FTSE chairmen and CEOs  to sign a letter of support in the same way as he pressured ministers,” reads a statement by Leave.EU, one of the groups campaigning to exit the EU. “One wonders what favours some of them expect in return.”

In spite of such cynicism, with household names including telecoms group BT, retailer Marks and Spencer, and oil giants Shell and BP, the letter is likely to sway some voters.

As the campaigns now steam toward a June 23 referendum, voters in the UK will be sifting through the arguments on both sides.

“In the next few weeks, the views of people like me will matter less and less, because the choice belongs to those who are really sovereign – the people of the UK,” wrote Johnson. “And in the matter of their own sovereignty the people, by definition, will get it right.”