On Sunday, about 850 people will cram into the Cambridge Junction – a venue typically attended by musicians and their fans.

There won’t be a moshpit or any smashing of guitars on this occasion, but it will still be fairly raucous, with the attendees calling loudly for their right to have the final say on any Brexit deal.

This is the latest rally in the People’s Vote’s Summer of Action campaign. It will be the third at which I have spoken, after Bristol and Newcastle. Other rallies will take place in Cardiff, Liverpool and Birmingham, culminating in a huge event in London on 20 October.

The previous People’s Vote march on Parliament Square in June was a major milestone for the campaign – 100,000 met that balmy Saturday afternoon to demand they have that final say. Any vote would, of course, include the option of an exit from Brexit, which is vital given the mess that has been made of the negotiations.

What has been so important about these rallies is that they have proven Brexit is not inevitable.

When the Liberal Democrats first took up this campaign two years ago, one of the big problems we faced was a sense that Brexit was inevitable.

Over recent months it has become increasingly accepted that there is a way out through these democratic means. That’s why so much polling now shows growing support for a people’s vote, while significant research this month found there are now more constituencies in favour of remaining in the EU than leaving.

We’re a democracy and the people have the right to change their minds when they have been presented with the reality of what Brexit will mean: a slowing economy; food, medical, labour and – to be fair, no one predicted this – even sperm shortages.

Dominic Raab: Government ready to deliver no-deal Brexit

Inevitability was the great weapon of the Brexit ideologues and they knew it. They recognise that we have neutralised this sense of “there’s nothing you can do now”. They will try whatever they can to restore that sense of inevitability.

This is why we are seeing claims that we have simply run out of time to legislate for a people’s vote before 29 March next year, the date that has been set for Britain to leave the EU.

But we haven’t run out of time.

The ideologues’ argument is partly based on the fact that primary legislation for the 2016 poll took seven months, including a long summer recess that would obviously not be a factor now.

The parliamentary timetable would be shortened dramatically given there is a pro-EU majority in the House of Lords that would most likely support a vote. Similarly, the number of supporters in the Commons is growing daily – what we need is for Jeremy Corbyn to come out in favour.

This would be the right position for him to take, given authoritative research from Queen Mary University has shown that 78 per cent of Labour members want the final say on any deal.

Ditto the SNP.

With a majority in both chambers, legislation could take weeks rather than months. After adhering to Electoral Commission advice and polling rules, the timetable is extremely tight but it is achievable.

Moreover, there is also the blindingly obvious move: extend Article 50.

Brexit: 10 of the most ridiculous headlines Show all 10 1 /10 Brexit: 10 of the most ridiculous headlines Brexit: 10 of the most ridiculous headlines The Sun, March 9 2016 This wholly false headline merited the first ruling by IPSO (the press regulator) under clause 1 of the revised Editor's Code of Practice. Clause 1 makes specific reference to newspapers printing "headlines not supported by the text" Brexit: 10 of the most ridiculous headlines Daily Mail, November 4 2016 In perhaps the most notorious front page of the past few years, the Mail derides the High Court judges who ruled that parliament must have a vote on whether to trigger article 50 and start the Brexit process Brexit: 10 of the most ridiculous headlines Daily Express, November 4 2016 In the Express' take on the same story, they manage to incorporate the Union Jack, allude to First World War propaganda, invoke memories of Churchill and, of course, state "Brexit means Brexit" Brexit: 10 of the most ridiculous headlines The Sun, March 29 2017 The Sun marked the day on which Mrs May triggered article 50 by projecting a huge and terrible pun on to the Cliffs of Dover Brexit: 10 of the most ridiculous headlines The Sun, April 4 2017 Referencing their notorious eurosceptic headline from 1990 (See: Up Yours Delors), the Sun stokes the flames of the brief Gibraltar dispute, a dispute in which Spain, the supposed aggressors, only joined to note that there was "no need for it" Brexit: 10 of the most ridiculous headlines Daily Mail, April 19 2017 This headline followed Mrs May's snap election announcement, which gave the Mail hope that dissenting opinions on Brexit would disappear Brexit: 10 of the most ridiculous headlines Daily Mail, December 14 2017 In recent months, the Mail has often forgone catchy headlines in favour of rambling rants, this is an early example aimed at Tory Brexit rebels Brexit: 10 of the most ridiculous headlines Daily Mail, January 31 2018 This headline (?) takes aim at the Lords over their repeated amendments to the EU Withdrawal Bill Brexit: 10 of the most ridiculous headlines The Sun, June 12 2018 On the day that the EU Withdrawal Bill is to be debated in the Commons, the Sun offers two choices to MPs, desperately including all conceivable imagery that might make Brits feel patriotic, which apparently includes the Loch Ness Monster Brexit: 10 of the most ridiculous headlines Daily Express, June 12 2018 On the same day, the Express lets MPs know what the consequences of the vote may be

There is no legal reason why we cannot do this. Article 50’s two-year exit timeframe was designed as a poison pill to make sure member countries were put off from leaving. What was not anticipated was the rise in anti-establishment feeling across the world that would lead to a country swallowing that pill.

Both the EU and British negotiating teams would welcome any extension given it is clear that such a big, complex secession cannot be achieved in just 24 months. I don’t believe there could ever be a deal as favourable to the UK as simply staying in the EU, but it has proved impossible to even achieve a half-baked solution in such a rush.

In short, where there is popular and political will, there is a way and we must not let the Brexiters fool us into thinking otherwise.

Brexit is not inevitable.