Unlike the breakaway SDP of the early 1980s, the Independent Group of former Labour and Conservative MPs has an unparalleled chance to campaign in a way that might well prevent them being squeezed to extinction by the UK’s all-powerful two-party electoral system.

Traditional party loyalties have been well and truly shattered by the European Referendum. The trauma of Brexit has left the support of millions of voters up for grabs.

By announcing their departure six weeks before the March 29 date for the UK’s exit from the EU, the Labour Gang of Seven (now eight), together with three former Conservative MPs, have engineered an ideal opportunity from which to present their demand for a People’s Vote.

The growing clamour for a second referendum – especially among younger voters – presents a platform that has been consistently rejected by Prime Minister Theresa May and has so far had scant appeal to the Labour leader Jeremy Corbyn.

Despite their best efforts, the Liberal Democrats have also failed to exploit to the full their strong pro-EU credentials.

A yearning among Remain supporters for a far more energetic campaign for a People’s Vote crosses the political divide at a time when traditional party loyalties have rarely been so weak and politics so fluid.

Numerous political pundits have suggested the formation of the Independent Group was ill-advised and premature, but their timing has enhanced their leverage at Westminster.

While the eleven ex-Labour and Conservative MPs have taken a gamble, they have caught the political tide.

Pressure for a second referendum is gathering pace and Theresa May might well be forced against her will to allow a People’s Vote on the EU withdrawal agreement as a condition of it being approved by Parliament.

In contrast to the hostility of the hard Brexiteers in the Conservative ERG  and the continued equivocation of Corbyn and the rest of the Labour leadership, the Independent Group could be present a pitch that would be positive, clear and decisive in favour of voters having the final say  – a demand that would chime with the equally strong appeal being made by the Liberal Democrats, Greens and SNP.

Should there be a second referendum the Independent Group would have every chance to put the two main parties to shame and if the outcome was a vote to remain in the EU it would well and truly break the mould of British politics.

Even if Theresa May avoids a People’s Vote and does manage to win over sufficient of the ERG hard Brexiteers to get her deal over the line at the last minute, it would be billed as a “Tory Brexit” that Labour had done too little to oppose – and that would only stiffen the resolve of aggrieved Remainers.

Already there is talk of the pro-EU cause morphing into Re-join – a successor campaign to fight for the UK to re-join the EU which would provide a continuing campaign platform for the Independent Group.

Theresa May’s failure from the start to work for a cross-party consensus on exiting the EU has left a legacy of political disillusion with the two-party system with little likelihood of the splits within both Conservatives and Labour being resolved any time soon.

As the next general election is not due until 2022 – and a much-wounded Conservative Party is unlikely to be in any hurry to go to the polls – the Independent Group have might well find that the much-feared two-party squeeze is nothing like as effective as it was in the 1980s.

Luck was on Margaret Thatcher’s side after her 1979 general election victory. Labour veered to the left under Michael Foot’s leadership, followed by the Gang of Four’s departure in 1981 to form the SDP.

But then the Falklands War intervened in 1982, presenting the ideal opportunity for Mrs Thatcher to seize the moment and opt for an early general election.

Given her success in the South Atlantic, the Conservatives’ 1983 landslide victory was never in doubt. The SDP-Liberal Alliance-SDP gained 25 per cent of the vote but only 23 Parliamentary seats – not the breakthrough which the Gang of Four had hoped for.

Brexit has divided the country unlike no other post-war crisis and out of the political fury, the Independent Group has united around the common cause of securing a People’s Vote and another chance to persuade the UK to opt to remain in the EU.

Eleven MPs left the two main parties trailing in their wake. The Wednesday round of Prime Minister’s questions was a surreal occasion as neither May nor Corbyn dared to mention the splits that had just emerged within their own parties.

For once the leaders of the two main parties were both so fearful of facing simultaneous political mockery that they shied away from the reality of the biggest breach in the two-party system to have occurred during their political careers.