Michel Barnier, the EU's chief Brexit negotiator, has suggested Boris Johnson is merely "pretending to negotiate" Brexit as his European counterparts await details of his proposals to replace the Irish backstop, a key part of the withdrawal agreement.

The UK prime minister has repeatedly promised to try and remove the backstop, a measure designed to ensure that no new border checks emerge on the border between Ireland and Northern Ireland, claiming that it is anti-democratic.

But Johnson's negotiators have so far only presented the EU with a draft of the withdrawal agreement with the backstop scrubbed out, and are not planning to take their plan to the EU until October, weeks before the Brexit deadline.

The EU's chief Brexit negotiator has accused Boris Johnson of only "pretending to negotiate" as the UK's scheduled exit date draws nearer.

Michel Barnier, who was addressing the EU Parliament on Wednesday morning, said the UK had failed to provide any "legally operative" solutions to the backstop following a meeting with European Commission president Jean-Claude Juncker in Luxembourg this week.

"The new UK government in Luxembourg this week outlined the aspects of the backstop which they don't like," Barnier told fellow MEPs.

"That's not enough, however, to move towards achieving a solution: We need a legally operative solution in the withdrawal agreement which [...] which addresses each one of the risks created by Brexit."

He added: "Almost three years after the UK referendum, I don't think that we should be spending time pretending to negotiate."

The comments follow reports that Johnson's chief of staff Dominic Cummings privately referred to Brexit talks as a "sham," suggesting that the UK was deliberately running down the talks to a no-deal Brexit.

Boris Johnson has repeatedly promised to try and remove the backstop, a measure designed to ensure that no new border checks emerge on the border between Ireland and Northern Ireland, claiming that it is anti-democratic.

But the UK government has not tabled a set of proposals which are designed to remove the need for any checks at the border, despite pledges to do so by the end of this week.

According to a Guardian report, which cited UK government sources, Johnson's negotiators have so far only presented the EU with a draft of the withdrawal agreement with the backstop scrubbed out.

The prime minister's team are reportedly reluctant to put forward a written proposal for fear it will be rejected out of hand or publicly rubbished.

Instead, Downing Street will reportedly unveil its new Brexit blueprint in October, just weeks before the Halloween deadline.

It is understood the plan will involve an "all-Ireland" market for food an agriculture, with customs and regulatory checks undertaken away from the border itself.

Risk of no-deal Brexit 'palpable'

European Commission President Juncker addresses the European Parliament during a debate on Brexit in Strasbourg Reuters

Meanwhile Jean-Claude Juncker, who addressed MEPs directly before Barnier, warned that the risk of a no-deal Brexit was still "palpable" following his meeting with Johnson in Luxembourg this week.

The House of Commons passed a law this month which would compel Boris Johnson to seek an extension beyond October 31 if he is unable to negotiate a deal, but Boris Johnson has repeatedly promised that he will not seek an extension, leading some opponents to speculate he is willing to break the law.

Juncker said: "The prime minister assured us that he continues to want an agreement. But, whatever happens, the United Kingdom will leave the European Union on 31 October with or without an agreement. That is why the risk of a no deal is palpable."

He said the European Commission was prepared to work "day in day out, morning until night" to find solutions but warned he was "not sure that we will get there."