Boris Johnson has been told that ironing out the details of his Northern Ireland plan would take “some two more months”

Germany has warned that Brexit will need to be delayed until next year even if European Union and British negotiators agree a new deal over the next 12 hours.

Optimism has grown on the European side that Boris Johnson will table a new proposal by midnight, paving the way for a breakthrough at an EU summit on Thursday.

The prime minister has been told, though, that ironing out the details of his complicated Northern Ireland plan would take “some two more months”. It sets up a scenario in which he would have to abandon his promise to take Britain out of the EU “do or die” on Hallowe’en and agree an extension to Article 50.

Michel Barnier: Brexit deal 'still possible, but more difficult'

The cabinet will be briefed at 4pm tomorrow about any