LONDON (Reuters) - British support for staying in the European Union now enjoys an 11-point lead over the rival “Out” campaign, according to an opinion poll that adds to a run showing rising support for the “In” side ahead of June’s referendum.

Students wait for the arrival of Labour MP Lucy Powell at Manchester Met business school in Manchester, England as part of her stay in Europe campaign on April 15, 2016. REUTERS/Andrew Yates

The ComRes telephone poll for the Daily Mail and ITV News showed 51 percent of Britons would vote with the “In” camp, supported by Prime Minister David Cameron, up three points from last month’s survey.

By contrast, support for Brexit fell a point to 40 percent, with the remainder listed under “don’t know”.

The ComRes survey of 1,002 people marks the sixth in a row from major polling companies to show strengthening support for the “In” campaign.

“The ‘Remain’ lead in the (EU referendum) continues in our trend series going back to May 2015,” said Tom Mludzinski, director of political polling at ComRes.

It also suggested there has been no change to Cameron’s standing among the public in the EU referendum debate, after his personal wealth came under scrutiny following the publication of the Panama Papers.

Just over a third said he would be important in deciding how to vote, unchanged from last month.

Later this week, Cameron hosts U.S. President Barack Obama, who is likely to suggest Britons should vote to stay in the bloc to preserve Britain’s wealth and its “special relationship” with the United States.

But the ComRes survey also brought a bit of good news for the Brexit camp: the proportion of Britons who said pro-Brexit London Mayor Boris Johnson would influence their views ahead of the referendum rose to 32 percent from 29.

Telephone polls have tended to give the “In” camp a bigger lead while online polls have the two sides running neck and neck.

A British exit from the EU would rock the Union - already shaken by differences over migration and the future of the euro zone - by ripping away its second-largest economy, one of its top two military powers and by far its richest financial centre.

Pro-EU campaigners, including former prime ministers Tony Blair and John Major, have warned that an exit could also trigger the break-up of the United Kingdom by prompting another Scottish independence vote if England pulled Scotland out of the EU.

Members of Britain’s “Out” campaign say such warnings are overblown and that Britain would prosper if it broke free from what they say is a doomed German-dominated bloc that punches way below its weight.