Euroscepticism has become a fringe movement within the Labour Party. Once a fashionable and popular cause, the reds are now mostly a pro-EU party. Brussels gained this popularity during Margaret Thatcher's premiership.

The Tory prime minister took on the unions and radically reformed Britain's employment laws. Labour and the Trades Union Congress (TUC) eventually turned to the continent in a bid, as they saw it, to protect the workplace from the Iron Lady.

Long gone are the days of Michael Foot campaigning for a Brexit from the European Economic Community (EEC) or Tony Benn, then Labour industry secretary, clashing with Harold Wilson ahead of the 1975 referendum on the UK's membership of the EEC.

But there is an old guard keeping the Labour Eurosceptic cause alive and, with David Cameron's promised referendum on the UK's membership on the cards, they have set up their own pressure group – Labour for Britain.

The organisation was co-founded by former sports minister Kate Hoey, Blackley and Broughton MP Graham Stringer and Luton North MP Kelvin Hopkins. The group also boasts the support of Labour donor John Mills, who serves as Labour in Britain secretary. He told IBTimes UK the organisation has a "change or go" strategy.

"We're open minded as to whether we should stay in or go, but it depends on very much how Cameron's negotiations go [with Brussels]. At the moment, it doesn't look like there are going to be any significant changes at all, which we think is very disappointing," Mills said.

He disclosed that if the prime minister is not able to secure substantial concessions from the EU, Labour for Britain would likely campaign for a Brexit. "We're not in that position yet, but if things don't buck up we might finish up there," the businessman said.

The group is just one of the EU-related organisations Mills has been involved with. He is a co-chairman of Business for Britain, the campaign group led by lobbying supremo Matthew Elliott (of Big Brother Watch, Taxpayers' Alliance and NOtoAV fame), is secretary to the Labour Euro-Safeguards Campaign group and was chairman of the Labour for a Referendum campaign.

One-man band

But the man doing the day-to-day running of Labour for Britain is Brendan Chilton. The campaign director ran as a parliamentary candidate for Labour in the Tory safe seat of Ashford at the general election and, like Mills, was previously involved with Labour for a Referendum campaign.

Chilton is a one-man band at the moment and commutes between Kent and London, while meeting Mills once a fortnight. He told IBTimes UK the number of staff will probably top out at a handful as the campaign grows.

"We are regularly contacting all Labour MPs, peers and council leaders and member of the Scottish parliament. But the first real big event is going to be the Labour annual conference, where we will try to influence debate within the Labour party," Chilton said.

He revealed "a couple of hundred" people have contacted Labour for Britain since news of its establishment broke and "up to 15 MPs" are interested in joining the organisation.

"We are not going to get as many as the Conservatives because there are obviously far more people who are concerned about the EU within the Conservative Party than the Labour parliamentary party, but we think, as we go along, we may exceed those numbers," he said.

Chilton admits the organisation is in its earlier stages. The group's website, usually a must-have calling card for any campaign in the age of the internet, is "under construction as we speak" and the campaign director is on the hunt for a "suitable and affordable" office in the capital.

But Labour for Britain will face stiff competition inside its own party as Alan Johnson, the popular former home secretary, is reportedly set to lead Labour's independent pro-EU campaign.

The 65-year-old, with his working-class and trade union credentials, represents a clear and present danger to the Eurosceptic cause. After all, he described the referendum vote to The Guardian as the "most important political decision" of his lifetime.

But could the pro-EU tide on the left be turning? The Rail, Maritime and Transport Workers (RMT) union has voted to campaign for a Brexit and the treatment of Greece's left-wing government by Brussels recently has pushed some British social democrats towards Euroscepticism.