Brussels is reportedly aghast that the prime minister’s senior adviser, Dominic Cummings, is telling British negotiators to stick by Brexit red lines and reject unfavourable compromises.

EU sources speaking to The Sun have claimed that Cummings is driving the hardline approach, with Britain’s deputy negotiator Oliver Lewis — like Mr Cummings, an alumnus of Vote Leave — following his ally’s lead and thereby proving to be the major impediment to a soft Brexit deal.

Sources also told the tabloid that they believe the Vote Leave faction in Number 10 is pushing for a “pure” no-deal exit. Under those circumstances, the UK leaves the EU’s institutions at the end of the transition period on December 31st, 2020, without a new deal, trading with the bloc instead on World Trade Organization (WTO) terms.

British sources deny the claims, saying that only Cummings and Mr Lewis are being pragmatic over the kind of deal that can be passed in the House of Commons. Prime Minister Boris Johnson’s 80-seat majority is founded on MPs who solidly back a proper Brexit without compromises that could infringe on British sovereignty.

It is not the first time that negotiators have appeared disturbed by Johnson’s allies demanding a proper and timely Brexit.

The UK officially left the European Union on January 31st, 2020, and is in a transition period, tied to the bloc’s rules and regulations, during which London and Brussels negotiates a future trade deal.

Theresa May-era career bureaucrats in the Civil Service were reportedly frustrated in April because their “true believer” colleagues — Johnson’s political appointees — in the negotiating process would not consider an extension to the transition period if a deal is not agreed. Neither would Johnson’s Brexiteers consider compromises that would leave Britain shackled to EU rules.

Brexit negotiations stalled earlier this month over what EU negotiator Michel Barnier called “significant divergences”. London and Brussels are at odds over several key issues over a future relationship. The UK wants to fully take back control of its fishing waters and agree on access on an annual basis; the EU, which currently lands more than 60 per cent of British territorial fish, wants long-term guarantees.

The EU insists the UK abides by Brussels regulations — to maintain a “level playing field” — for business to stop Brexit Britain outcompeting the EU-27 in the region; the UK wants to be free of foreign regulations, especially if they conflict with signing trade deals with other countries.

The EU also wants any future trade disputes to be arbitrated by the European Court of Justice; the UK wants an independent judiciary that is not tied into Brussels’ institutions.

Boris Johnson put into law that the UK must leave the EU on December 31st, recently saying that while he hopes a deal can be agreed on by the end of Summer, there still remains the option of leaving without an agreement and possibility of signing a partnership framework that facilitates trade: what he refers to as an “Australia deal”.

This month, German Chancellor Angela Merkel told the EU to prepare for no deal.