In 1981, the Gang of Four split from Labour to form the Social Democratic party (SDP). The new party did not come close to power, but it won a huge number of votes – 7.8m in 1983 – and kept Labour out of government for a generation. In this time, Margaret Thatcher set fire to the fabric of British society: depriving schools and hospitals of funding, annihilating British industries, disempowering unions and accelerating privatisation.

Growing up in Tottenham with a single mother who worked several jobs to put food on the table, I experienced first hand how splits on the left let Thatcher turn Britain cold.

Today, Labour’s vision for a fairer society faces a similar threat. The development of a new centrist rival has been an open secret in the Westminster tea rooms for months. Funding from individuals and big business is rumoured to be already in place. As the New Statesman reported, a split has become “inevitable”.

The clock is ticking for us to save the country from this hard-right Tory fantasy

There’s one key reason for this: Brexit. The public has changed its mind on the European Union. Recent polling showed that 100 constituencies that voted to leave the EU have now switched support to Remain; 69% of Brits think Brexit is going badly. Of those asked, nearly twice as many support a new referendum on the government’s final deal than oppose it. But voters who recognise retaining EU membership as the biggest issue of our time are being deprived of an electorally significant opposition party to support.

For the past two years, my party has remained stubborn in its commitment to Brexit, while never fully ruling out the possibility of a referendum on the final deal. While I would never have supported it, tacticians may once have been able to justify a position of “constructive ambiguity”. This time has now passed. With just months remaining until we leave the EU, the clock is ticking for us to save the country from this hard-right Tory fantasy, which was built on xenophobia, lies and a law-breaking campaign.

As the French president, Emmanuel Macron, made clear, the Chequers agreement in its current form will be rejected because it requires the “unravelling” of core parts of the EU. Meanwhile, the reality of the no-deal alternative is so bleak, it is almost impossible. The only deal acceptable to EU that gives the UK the access it needs is something close to European Economic Area membership. Very soon, Labour will have to decide whether to save Theresa May and vote for this or call for a people’s vote, which offers the chance to remain in the EU.

If the official opposition does not stand by the inevitable results of Keir Starmer’s six tests and oppose Brexit, a new party will, with the clear purpose of restoring the UK’s economy, our country’s place at the top table of diplomacy and stealing the open, internationalist vision that for so long has been associated with Labour. It’s impossible to predict how well this party will do. Whether it eventually wins 20 seats or 200, a new party will more than likely block us, the Labour party, and condemn Britain to at least another decade of disastrous Tory dominance.

Preventing a vote on the biggest political decision this country is facing would be a betrayal

In the 1980s, Labour had no simple way to kill off the SDP. Today, we can do it with a single press release. A new centrist party without the Brexit issue to distinguish itself would be like a rocket without fuel. By calling for a referendum that crucially offers Britain the right to remain in the EU, Labour would capitalise on the public’s change of mood. It would also unite Labour members, 75% of whom want a vote, as well as the PLP, which at heart remains strongly pro-EU.

Much of the excitement around Jeremy Corbyn’s election as Labour leader has been based on his promise to democratise the party. For this, he deserves credit. But to honour this promise, the party conference must be allowed to determine Labour’s Brexit position. Preventing a vote on the biggest political decision this country is facing would be a betrayal.

The strategic argument for Labour’s opposition to Brexit has emerged over time, but the underlying reasons have been self-evident from day one. The party of Keir Hardie simply cannot vote with the government as it kneecaps our economy, savages environmental and workers’ rights and constrains the horizons of our young supporters to this small island, against their will.

If we want to build a fairer and more equal Britain, it’s time for Labour to stop pussyfooting around and lead calls for a people’s vote.