I know I am in a minority in thinking Brexit can be stopped. I am not in a minority in thinking it should be. Yes, I meet people who say we have had the vote, now get on with it. But I meet many more who say what on Earth are we doing? Who says that if you see a car heading towards a cliff edge you change direction. Or you slam on the brakes. You admit that the route you are taking is not the one you thought it would be.

Theresa May says in her Brexit white paper that her greatest asset in the negotiations ahead is the strength and support of 65 million people.

Prime minister, you do not have the support of 65 million people for the hard Brexit route you have chosen. You don't even have it even among many among the 52% who voted for the extra money for the NHS that isn't coming. Who voted because they believed the Leave liars when they said we would stay in the single market and the customs union and a good deal with the EU was guaranteed.

You certainly don't have it among the young. I challenge any Brexiteer to go to any school or college and find anything but a huge majority who want to stay in Europe and who believe the older generation and their politicians are stealing their future from them.

Can any Brexiteer name a country anywhere in the world anytime in history that built success by actively governing against the interests of the young? A government that governs to recreate a sepia image of the past rather than fulfil a bright vision for the future is a government that is doomed to fail.

Many of those who voted for Brexit will not be with us when the 16 and 17-year-olds denied the vote last year have to deal with the consequences. By the time we are out demography tells you there will definitely be a majority to be back in.

So how do we stop this? By persuading the country to change its mind. By persuading Theresa May to change her mind. She does you know. After all, until 23 June she was soft Remain. Allegedly. Now she is the high Priestess of hard Brexit.

We have to persuade Jeremy Corbyn to change his mind and his modus operandi so that his statement that "the real fight starts now" after he led his MPs into the valley of fear and loathing with the Tories actually means something.

We have to persuade those with legitimate fears about immigration changing their communities too quickly, or worries about the Eurozone, that this is not the route to meet those concerns.

We have to persuade those who feel as we do to make themselves heard, not to be cowed by the bullying and intimidation of the Brextremist Lie Machine papers and not to be fooled by the sense of inevitability Mrs May is trying to exploit. Of course, she is in a rush. Because the more time the public have to realise where this is heading the more they will demand the right to have another say.

Yes, the people have spoken. Yes, the democratic will must be respected. But democracy includes the right to change your mind. Can anyone show me the place in our constitution that says if you lose a vote it means you have to accept and agree with the arguments you lost to?

And ask yourself. Did the eurosceptics stop fighting to get out of the EU when the country voted to get in back in the 1970s? Well, now the country has voted to come out we should fight to stay in. Have the SNP given up the fight for independence because of one vote on one day in history? No. Did Barcelona give up their dream of the champions league when they needed three goals to beat PSG with just a few minutes left? No. They fought back. And we must fight back now.

We are the underdogs now. We are the insurgents. And if we stay strong, spend every day in the task of persuasion, beating Brexit can join Barcelona beating PSG in the annals of great comebacks that bring joy to the world.

Marching for change

Don't let anyone tell you it is traitorous to want to stop this madness. It is the best form of patriotism to try to stop your country from making what you believe will be a catastrophic error, whatever the good motivations of at least some who made that choice. Which is why we are the people who should be flying the British flag not the Ukippers who have stolen it. So march today and fight tomorrow. Advert time. Stop reading the Lie Machine papers of the tax dodgers and foreigners who control our media and start spreading the word about my new paper The New European. The 48-pager for the 48%. Let's grow that number.

I was at Martin McGuinness' funeral this week. Thousands of people. Many who had spent much of their lives trying to kill each other. And who delivered the peace we have there – now at risk because of the possibility of a hard border and a weakening post-Brexit economy on both sides of it – because people had the courage to change their mind. To admit they had for too long done the wrong thing and should do the right thing.

My old Friend Philip Gould always used to say you must trust the people to do the right thing. And sometimes that means admitting you've done the wrong thing and changing course. Last June this country voted for an act of economic and political suicide. We may not stop it. We may fall over the cliff. But at the very least everyone here should be able to look their own children and grandchildren in the eye and say, "I gave it my all to try to stop it."

So let's give it our all. Let's fight back and win. Fight back against Brextremists in the government and liars in the media. It is time to take back control, ladies and gentlemen, so that we can keep Britain great, for good. Thank you.