Lord Frost must drop his confrontational style of negotiating if Britain and the EU are to rebuild their strained relationship, Brussels sources have warned. The rebuke was angrily rejected by the Government, which insisted that former Brexit negotiator Lord Frost was “the best person” to reset UK-EU relations. Lord Frost, who negotiated the EU trade deal last deal, will oversee thorny talks over the implementation of the Northern Ireland Protocol from Monday after being promoted to a minister in Boris Johnson’s Cabinet. During last year’s Brexit trade talks, he ruffled feathers in Brussels with his uncompromising insistence on the EU respecting the UK as a “sovereign equal”. "The EU and UK relationship is in dire need of more consensus, unfortunately Lord Frost is, so far, better known for confrontation,” an EU diplomat told the Telegraph. “Putting the relationship on ice is not an option. Britain and the continent are too close, too interlinked and there's too much going on affecting both sides of the English Channel.” “Based on evidence so far this year, the EU’s efforts can hardly be described as having promoted harmony,” a UK government source said. The source said that European Commission moves towards a coronavirus vaccine export ban and its short-lived threat to impose a hard border on the island of Ireland to enforce it were “concerning”. The source added, “We are working at pace to ensure a friendly and productive relationship. The best person to lead that effort is Lord Frost.” The EU warning came after reports that senior figures in Brussels hoped to “reset” the relationship with Britain. Relations have been further strained by rows over the implementation of new customs arrangements in Northern Ireland and the status of the EU's ambassador to the UK. An EU official said, “We know Lord Frost and I’m sure we will be more than capable of working with him and finding solutions.” Recent meetings between the two sides over the protocol have failed to find agreement on the extension of various grace periods to, for example, ensure continued supermarket supplies to Northern Ireland from Great Britain. The RTE broadcaster reported that the reset could be a meeting between Boris Johnson and senior EU figures such as European Commission president Ursula von der Leyen. The EU is due to ratify the new trade deal, which has been provisionally applied, in April. This would be a good moment to draw a line under past disagreements, especially if new agreements on the grace periods on the protocol can be agreed in time The EU official said, "This would be a nice thing to happen but we are not holding our breath. The timeline sounds about right. I’m not so sure if a ‘reset’ is possible, but I think it’s admirable that we’re at least trying." The reset would be aimed at drawing a line under the tetchy relations that have bedevilled London and Brussels since the UK left the Brexit transition period at the end of last year. A UK government spokeswoman said, “The deal we struck with the EU is the beginning of our new partnership in Europe, with new stability and certainty around our future relationship. “It will build on our shared history of friendship and cooperation, but as sovereign equals, with greater democratic autonomy and a clear, independent voice to speak and act on our priorities.” Britain and the EU were reported as nearing an agreement on a memorandum of understanding on financial services on Friday, which could be a small step to securing access to the Single Market for some UK firms.