According to a leaked document sent to the Treasury, the chancellor, Philip Hammond, has been told to prepare for an amendment that Number 10 says could be put down by an “influential Conservative backbencher”, demanding that “payment of the financial settlement to the EU will be halted until and unless the future relationship has been concluded”.

The chancellor and his team will have to send a draft response combating the amendment to Downing Street for review.

Liam Fox has been asked to prepare for a possible amendment tabled by pro-Remain rebels requiring him to provide updates on how his negotiations for new trade deals are going.

The mock amendment would require the trade secretary to give a quarterly “update on the UK’s progress on negotiating International Trade Agreements”, and if he failed to seal any trade deals, hold a Commons vote on rejoining the EU.

Fox famously promised, “We'll have up to 40 [trade deals] ready for one second after midnight in March 2019.”

May’s team are preparing for a raft of amendments from the Labour side, too. Under one scenario drawn up by DExEU aides, Labour MP and chair of the Home Affairs Select Committee Yvette Cooper would table an amendment demanding further protections for EU citizens.

Home secretary Sajid Javid has been asked to draft a response if Cooper attempted to insert a clause banning any new UK laws or regulations that “imposed fees or penalties on EU citizens” or “allow any distinction to be made between the arrangements of EU citizens and UK citizens in actions of public authorities”.