LONDON — The British government is fighting back against criticisms that it is divided and unprepared for Brexit, with two Cabinet rivals over Europe issuing a joint statement.

Trade Secretary Liam Fox, a strong supporter of leaving the European Union, and the more pro-EU Treasury chief Philip Hammond, write in the Sunday Telegraph that there will be a “time-limited” transition period after Britain formally leaves the bloc in 2019.

The government also says it plans to publish a set of detailed proposals on customs arrangements and other issues starting this week.

The EU refuses to negotiate the bloc’s post-exit relationship with Britain until sufficient progress has been made on three issues, including the size of U.K.’s exit bill.

Britain wants to show progress so the broader negotiations can start by October.