Once mistaken for fellow blond Donald Trump by a passerby in New York, London Mayor Boris Johnson hopes his own gift for grabbing headlines and charming voters can persuade Britain to vote to leave the European Union at a June 23 referendum.

"They both come from incredibly privileged backgrounds and yet they are both supported by, if you like, for want of a better expression, the common man," said Joe Twyman, head of political and social research at pollster YouGov.

With British public opinion evenly split on whether to remain a member of the EU, the world's largest trading bloc, and many voters yet to make up their mind, Johnson, 51, is hoping to become the galvanizing figurehead for the "Out" campaign.

Trump, with an anti-immigrant stance and blunt, combative style, has captivated American media and mobilized latent grassroots support to move from rank outsider to the Republican party's likely presidential candidate in the November election.

A British exit would batter the EU by ripping away the bloc's second-largest economy and wealthiest financial center at a time when it is struggling to manage mass migration and coax economic recovery from the embers of a financial crisis.