Best for Britain have launched a £200,000 national campaign supporting a public vote on the final Brexit deal.
Best for Britain, the pro-EU campaign group, will reveal a billboard van on Tuesday morning.
The billboard van encourages the British public to press the ‘emergency stop button’ and have a vote on the final Brexit deal.
On Tuesday, the van will call on MPs to give people a final say on Brexit, as Parliament returns from summer recess.
The van will circle Westminster before travelling across to Waterloo, up to Trafalgar Square and back to Parliament.
‘2.6 million Leave voters switch their support’
Westminster MPs return to Parliament as Brexit Secretary Dominic Raab will update the Commons on the latest developments following his talks with EU negotiator Michel Barnier.
This follows as Brussels rejected the Prime Minister’s Chequers plan.
Heidi Allen, the Conservative MP for South Cambridgeshire acknowledged some of her fellow pro-EU Conservatives viewed Chequers as a "complete non-starter" but others, like her, were prepared to give it a "little bit longer".
She told the BBC's Newsnight: "The only way any of us are going to come through this is with a little bit of compromise on both sides.
"Nobody is going to get exactly what they want but you have to start somewhere."
A new study found that 2.6 million Leave voters have switched their support to Remain.
The study carried out by Focaldata for Best for Britain, found that 2.6 million Leave voters had changed their support, while 970,000 moved the other way - a net gain for the pro-EU side of 1.6 million.
The study was based on two YouGov polls that surveyed more than 15,000 people.