British Brexit negotiators are closing in on securing a deal on the transition period and have surprised their European Union counterparts with their “strong will” to strike an agreement to effectively prolong Britain’s membership of the single market and customs union for about two years after March 29 2019.

London is targeting the March 22 European Council summit to secure agreement on the transition period, which is needed to give valuable time for the government and businesses to prepare for Brexit. During transition, Britain will lose all EU voting rights but will have to implement all new and existing EU laws.

Sources revealed that the European Commission, which leads Brexit talks on behalf of the bloc, were “impressed” by the British team during negotiations in Brussels last week.

“The UK was seriously prepared,” said one EU diplomat, “it seems that ‘let’s get on with it’ means ‘let's get on with it’.”

Theresa May had invited ridicule in some quarters in Brussels by finishing her Mansion House speech by saying “Let’s get on with it”. The UK has been accused of having no clear plan or strategy to keep the negotiations moving.

Junior Brexit minister Robin Walker on Monday said Britain was “very close” to a deal. "We recognise how important it is to secure the deal on the implementation period as soon as possible. I want to stress that we are very close to a deal at this time," Mr Walker said in a speech at the Institute of Directors in London.