Theresa May has divided her top team of ministers into two working groups to hammer out their differences on Brexit.
The cabinet is split over how to manage customs arrangements with the EU.
Brexiteers such as Boris Johnson are against Mrs May's preferred option of a "customs partnership", which is backed by Remain-voting ministers.
Mr Johnson's preferred model relies on technology to minimise customs checks. The EU has expressed doubts about whether either option would work.