Ministers want the post-Brexit transition period during which Britain will follow EU rules to be determined by how long it takes the Government to introduce measures needed for life outside the union, a leaked official document shows.

The paper said the length of the “status quo” transition “should be determined simply by how long it will take to prepare and implement the new processes and new systems that will underpin the future partnership”, which “points to a period of around two years”.

The Government has previously stated that the period should be “strictly time limited” but an end date is not proposed in the document leaked to Bloomberg.

Instead it points to a desire to “discuss with the EU the assessment that supports its proposed end date” of December 31 2020.