"We will leave the customs union and be free to negotiate the best trade deals around the world as an independent, open, trading nation", the ministers said, adding that the government was committed to make sure there "will not be a cliff-edge when we leave the EU in just over 20 months' time".
Hammond has spent the last few weeks arguing strongly for a lengthy Brexit transitional period, to the delight of pro-Europeans, and earlier this summer he hinted that he was considering an arrangement that would in effect keep the United Kingdom in the customs union, and therefore unable to sign bilateral trade deals with non-EU countries, for the period between Brexit and the final settlement coming into force.
The finance minister's Brexit department said it would publish some papers, including plans for a new customs arrangement and how to resolve the problems of a non-existent border between Ireland and Northern Ireland.
Britain is struggling with the negotiations, and the pace has sparked concerns that a March 2019 exit deadline will arrive without a deal being reached.
Sources at Britain's department for exiting the European Union said the "future partnership" papers would show that the British government was ready to move on to the next stage of the negotiations. The two leading politicians said the government wanted to ensure "there will not be a cliff-edge when we leave the EU".
During their second round of talks held in July, the European Union and UK Brexit teams failed to reach an agreement on 22 of the 44 issues under negotiation.
The ministers were seen being on opposing sides on Brexit, with Hammond championing a business-friendly approach where Britain gradually leaves the European Union while Fox sought as short a transition as possible, and for Britain to have the freedom to immediately negotiate trade deals.
"We've been crystal clear that issues around our withdrawal and our future partnership are inextricably linked, and the negotiations so far have reinforced that view". Prime Minister Theresa May wants an accord before leaving. The first of these will set out proposals for a new customs agreement, it said.
"By triggering Article 50 in March of this year we leave in March 2019, what the transition period will look like is down to the negotiations", he said during a surprise appearance at Alex Salmond's show at the Edinburgh Festival Fringe.