Emblazoned with the slogan "is it worth it?", the bus will be touring the country.
Organisers say 20 grassroots groups have scheduled the bus tour, which will visit all corners of Britain from Scotland and Wales to various English regions and cities.
"But we have the right to make up our own minds". The country's main political parties agree that the decision can't be reversed.
The legal text sets out the U.K.'s proposals for a transitional agreement to take effect after it leaves the European Union in March 2019.
The opposition Labour party said the letter exposed the "deep divisions" in the Conservative Party.
She said Renew's message is: "It's not too late".
The figure was inflated - Britain's net contribution to the bloc is about half that - but it stuck, and many believe it helped swing the referendum in favour of leaving.
"This will be a crucial part of ensuring our future economic partnership is as open, and trade remains as frictionless, as possible", Mr Davis said. How much access will Britain have to the bloc's single market?
Conservative MP Kwasi Kwarteng, an aide to Chancellor Philip Hammond, explained the latest statement on the customs union was "perfectly consistent" with what the government had been saying all along, given that Prime Minister Theresa May had been "pretty clear" for more than a year that the United Kingdom would be leaving.
The letter published on Wednesday called on Mrs May to ensure that Britain had "full regulatory autonomy" from the European Union as well as being free to negotiate and sign deals with other countries.
Mr Holding is leading a cross-party group of U.S. politicians. The party hopes to run candidates for all 650 seats in Parliament in the next general election. And as a party founded by London-based professionals, Renew may struggle to connect with voters in less metropolitan, economically struggling regions where support for Brexit is strongest.
"If the best this Government can do is promise Britain will not turn into a "Mad Max" nightmare - it's no wonder people are anxious about their post-Brexit lives, " said general secretary of the GMB union, Tim Roache".
Boris Johnson said just a few months ago that the Brexit vow should have been a £438million promise.