Campaigners for a referendum on the Brexit deal are promising the “biggest ever pro-European march”, as their hopes grow for a fresh public vote.

The demonstration – to be staged on the second anniversary of the Leave vote in June – will kick-start a “summer of action and mobilisation”, they say.

Supporters of giving the people a “final say” on the exit deal negotiated by Theresa May expect to attract huge numbers from across the UK and as far afield as Gibraltar.

The march, on 23 June, comes after the government acknowledged that MPs have the power to force a new referendum by amending a vote on the withdrawal agreement in the autumn.

Steve Baker, the Brexit minister, said the crucial vote would not – as expected – be a “take it or leave it” choice, because “parliament can always seek to amend motions”.

Now the March for a People’s Vote will, for the first time, bring together ten major pro-EU campaigning organisations under the same banner, through central London.

James MacCleary, of the European Movement UK, one of the groups behind the campaign, urged people to join the march to “make such a noise about it that is so loud it will be impossible to ignore.”

Femi Oluwole, of Our Future Our Choice, said: “Young people have the most at stake here and, if we leave the EU in March 2019 without a People’s Vote, half a million young people will have been denied any say about the biggest decision on their future.”

Brexit threatens life on the Irish border: in pictures Show all 15 1 /15 Brexit threatens life on the Irish border: in pictures Brexit threatens life on the Irish border: in pictures An abandoned shop is seen in Mullan, Co Monaghan. The building was home to four families who left during the Troubles. The town was largely abandoned after the hard border was put in place during the conflict. Mullan has seen some regeneration in recent years, but faces an uncertain future with Brexit on the horizon Reuters Brexit threatens life on the Irish border: in pictures A defaced ‘Welcome to Northern Ireland’ sign stands on the border in Middletown, Co Armagh Reuters Brexit threatens life on the Irish border: in pictures Mervyn Johnson owns a garage in the border town of Pettigo, which straddles the counties of Donegal and Fermanagh. ‘I’ve been here since 1956, it was a bit of a problem for a few years. My premises has been blown up about six or seven times, we just kept building and starting again,’ Johnson said laughing. ‘We just got used to it [the hard border] really but now that it’s gone, we wouldn't like it back again’ Reuters Brexit threatens life on the Irish border: in pictures Farmer Gordon Crockett’s Coshquin farm straddles both Derry/Londonderry in the North and Donegal in the Republic. ‘At the minute there is no real problem, you can cross the border as free as you want. We could cross it six or eight times a day,’ said Crockett. ‘If there was any sort of obstruction it would slow down our work every day’ Reuters Brexit threatens life on the Irish border: in pictures John Murphy flies the European flag outside his home near the border village of Forkhill, Co Armagh Reuters Brexit threatens life on the Irish border: in pictures Potter Brenda McGinn stands outside her Mullan, Co Monaghan, studio – the former Jas Boylan shoe factory which was the main employer in the area until it shut down due to the Troubles. ‘When I came back, this would have been somewhere you would have driven through and have been quite sad. It was a decrepit looking village,’ said McGinn, whose Busy Bee Ceramics is one of a handful of enterprises restoring life to the community. ‘Now this is a revitalised, old hidden village’ Reuters Brexit threatens life on the Irish border: in pictures Union Flag colours painted on kerbstones and bus-stops along the border village of Newbuildings, Co Derry/Londonderry Reuters Brexit threatens life on the Irish border: in pictures Grass reflected in Lattone Lough, which is split by the border between Cavan and Fermanagh, seen from near Ballinacor, Northern Ireland Reuters Brexit threatens life on the Irish border: in pictures Donegalman David McClintock sits in the Border Cafe in the village of Muff, which straddles Donegal and Derry/Londonderry Reuters Brexit threatens life on the Irish border: in pictures An old Irish phone box stands alongside a bus stop in the border town of Glaslough, Co Monaghan Reuters Brexit threatens life on the Irish border: in pictures Billboards are viewed from inside a disused customs hut in Carrickcarnon, Co Down, on the border with Co Louth in the Republic Reuters Brexit threatens life on the Irish border: in pictures Seamus McQuaid takes packages that locals on the Irish side of the border have delivered to his business, McQuaid Auto-Parts, to save money on postal fees, near the Co Fermanagh village of Newtownbutler. ‘I live in the south but the business is in the North,’ said McQaid. "I wholesale into the Republic of Ireland so if there’s duty, I’ll have to set up a company 200 yards up the road to sell to my customers. I’ll have to bring the same product in through Dublin instead of Belfast’ Reuters Brexit threatens life on the Irish border: in pictures A disused Great Northern Railway line and station that was for customs and excise on the border town of Glenfarne, Co Leitrim Reuters Brexit threatens life on the Irish border: in pictures Alice Mullen, from Monaghan in the Republic of Ireland, does her shopping at a former customs post on the border in Middletown, Co Armagh. ‘I’d be very worried if it was a hard border, I remember when people were divided. I would be very afraid of the threat to the peace process, it was a dreadful time to live through. Even to go to mass on a Sunday, you’d have to go through checkpoints. It is terribly stressful,’ said Mullen. ‘All those barricades and boundaries were pulled down. I see it as a huge big exercise of trust and I do believe everyone breathed a sigh of relief’ Reuters Brexit threatens life on the Irish border: in pictures A bus stop and red post box stand in the border town of Jonesborough, Co Armagh Reuters

And James McGrory, of Open Britain said: “Brexit will affect everybody in the country, which is why it should not be left to 650 politicians in London to decide our future but to all 65m people. That is why so many are demanding a People’s Vote on the final Brexit deal.”

The campaign has launched a crowd funding appeal to raise £100,000 to meet the costs of organising and advertising for the march.

Ms May has firmly rejected a further referendum, but some pro-EU Tories believe she could yet accept one if it appears the only way to keep her warring party together on Europe.

Similarly, although Jeremy Corbyn has said Labour does not back another referendum, he has left the door open to a change of mind.

There is also polling evidence that public support is growing for a referendum on the Brexit deal, amid continuing confusion about both the planned transition period and the final trade deal with the EU.

Opinion appears to be shifting as the negotiations remain bogged down on how to avoid a hard border in Ireland and with the details of a trade deal unlikely to even be discussed until after departure day.

Some Tory MPs also believe a legal challenge – to require a further referendum before Brexit can go ahead – could yet put the government in difficulty.