By Elizabeth Piper
LONDON (Reuters) - Among the ranks of campaigners to keep Britain in the European Union is a small group of Prime Minister David Cameron's closest advisers. For these aides, the scale of victory is as important as victory itself.
This team is targeting close to 60 percent of the "Remain" vote in a June 23 referendum that will decide whether Britain stays in the EU or leaves, members of Cameron's inner circle told Reuters in interviews. That, they believe, is the minimum to bury the "Europe question" and ensure Cameron is able to serve out his term to 2020.
Polls suggest the vote is too close to call. Yet these advisers believe scraping through is not enough. Without a clear margin, Cameron will remain vulnerable on an issue that brought down two of his predecessors, Margaret Thatcher and John Major, and has bedeviled his Conservative Party for decades.
Already some anti EU "eurosceptics" in the party are plotting to try to force Cameron aside regardless of the referendum outcome, according to two Conservative Party sources. The greater the margin of victory, the smaller their chance of success, the aides say.
The advisers' tactics include the targeted use of social media - mothers of young children are more likely to engage with the campaign in the evening, for instance. They have organized 'theme weeks', such as one that draws in pro-Europeans in the opposition Labour Party, and for every new statistic rolled out in the debate there is a carefully crafted back story.
A spokesman for Cameron said the prime minister was committed to winning the referendum but declined to speculate on the scale of victory he wanted. A source close to the prime minister said he was conscious the bigger the win, the stronger his position.
"And even then putting the party back together will not be easy," said the source, who like several others interviewed for this article declined to be identified because they were not authorized to discuss the campaign publicly.
Not only is the country divided over EU membership but almost half of the Conservative Party's lawmakers and some members of the cabinet are campaigning to leave the 28-member bloc. The source close to Cameron said the PM was 'edgy'.
So Cameron has turned to trusted advisers and experienced election hands to make sure "things fly through properly and he has people who understand what he means and how he works".
The prime minister is relying most heavily on roughly half a dozen aides who were central to the Conservatives' election victory last year and Scotland's vote against independence in 2014.
The group includes his "secret weapons" in the 2015 parliamentary election, Craig Elder and Tom Edmonds, who target swing voters with online videos and social media adverts.
Elder and Edmonds, digital strategists, left their jobs at the Conservative Party after helping Cameron win the 2015 election to set up their own agency, which is retained by the Remain campaign.
They declined to comment for this article but they have in the past outlined their strategy, which includes targeting different groups at the most effective times of the day - say a 40-year-old mum of two on social media in the evening, "when the kids have gone to bed".
The man behind Remain's field team, Stuart Hand, helped run the Tory ground campaign during the 2015 election.
Two other advisers, Andrew Cooper and Stephen Gilbert, bring polling advice and election experience. Both have been close to Cameron for about two decades.
Once a week, at least one Remain campaign adviser attends the prime minister's 8:30 a.m. and 4 p.m. meetings in his Downing Street office. As June 23 draws closer, Cameron will be briefed almost continuously.
Dozens of campaigners employed by the Remain campaign will be working round the clock. One new team member says he was advised to stock up on cans of baked beans and new underwear because "there will be no time to eat or wash".
Also in Downing Street, Ameet Gill, a long-serving aide, fills in "the grid", a sort of diary, to set the prime minister's EU agenda.
Downing Street coordinates with the EU referendum unit, which manages the government message, and with Remain, or The Britain Stronger in Europe campaign, run from an office three miles (five km) away in the City of London.
Cameron is unable to visit the Remain team's base in Cannon Street in central London often because of government business, so he relies on Gilbert, who has taken a leave of absence as deputy chairman of the Conservatives, to liaise, said a source close to the campaign. Gilbert could not be reached for comment.
The June 23 vote will determine Cameron's political legacy and the future of Britain.
He called the referendum under pressure from members of his own party and in response to a growing electoral threat from the UK Independence Party, an anti-EU force.
Cameron has thrown himself into campaigning, touring the country to try to convince people to support remaining in the European Union, repeating his mantra that Britain is "stronger, safer and better off" in the bloc.
He has visited workers in finance, car manufacturing, the defense industry, shared the floor with political opponent turned EU ally Brendan Barber, a former trade union leader, and met often hostile students to try to persuade Britons to vote to stay in the EU.
If securing his legacy means some opponents of EU membership decide to leave the Conservative Party, then "so be it", said one of the sources close to the campaign.
Cameron's spokesman said it was up to individuals to decide whether to remain in the party after the vote, but added that while he expected "the vast majority of the party" will respect how Britain votes, "there will be some people who continue to believe very strongly that we should leave."
For Britain Stronger in Europe, which unites pro-Europeans from several political parties, the prime minister's role is key, said James McGrory, its chief campaign spokesman.
McGrory, a former adviser to Liberal Democrat deputy prime minister Nick Clegg during the 2010-2015 coalition government, underlines that the Britain Stronger in Europe is an umbrella group which allows all parties to press the campaign.
Cross-party cooperation is rare in Britain, where the left-right political divide often creates a tribal atmosphere in parliament. But Cameron needs opposition Labour and Liberal Democrat to mobilize their voters.
TEAM BACK TOGETHER
Cameron's reliance on a small circle of advisers has not been universally well received. Some eurosceptic members of the Conservative Party have accused Cameron of stacking the odds in his favor.
According to aides, Cameron is willing to weather the storm and is convinced he can win.
Cooper said in his personal opinion the goal was that once the referendum was over, Cameron would be able to return to the election program he set out last year - to tackle poverty, to boost home ownership and to end discrimination.
"If the Remain campaign wins by a clear margin, the Conservative Party must quickly move on from the EU issue," he said. "On the Saturday morning we should go back wholeheartedly to the agenda David Cameron set out in his speech to last year's party conference, driving the Conservative Party onto the center ground and bolting it there."
(additional reporting by William James, editing by Janet McBride)