The spokesman mentioned: 'Michel Barnier debriefed COREPER (The Permanent Representatives Committee) yesterday, where member states agreed that the United Kingdom proposals do not provide a basis for concluding an agreement'.
If Johnson fails to reach a deal by October 19, he must ask Brussels to delay Brexit under a law passed by British MPs to try to prevent a "no-deal" divorce.
"We are concerned that he (Johnson) can not be trusted to do what he has said to the court", said Maugham.
"One thing is clear: Johnson's Brexit plan can't be negotiated [before] October 31".
British media speculated that Johnson might seek to sabotage any extension request he is forced to make against his will. Webster said there is no need for a court intervention since the government has made its intentions known.
Revelations made in UK Government documents given to a Scottish court come as a direct contradiction to the plan the Prime Minister delivered when he said the UK will leave the European Union on October 31 - even if it's without a deal.
He said the government still wants to leave the union on October 31 and plans to do so.
On Thursday, Mrs Foster accused the Irish government of trying to "ride roughshod" over unionism, as she criticised Dublin's rejection of the UK's latest Brexit plan.
The Taoiseach said the exact amount that the government will provide for Brexit contingency measures was not yet settled.
But the PM later said the options facing the country were his proposed new Brexit deal or leaving without an agreement, "but no delay".
Boris Johnson has reportedly been given one week to improve his latest Brexit plan or European Union leaders will not discuss it at a summit in two weeks' time.
His office did not offer an immediate response to the government submission read in court.
Conservative Party lawmaker Steve Baker, leader of a prominent pro-Brexit group in Parliament, said the court statement "does not mean we will extend". It does not mean we will stay in the European Union beyond October 31.
Mr Johnson has beforehand mentioned he would moderately be "dead in a ditch" than ask for a delay.
The EU dealt a heavy blow to the PM's new Brexit proposals on Friday, and anticipated weekend talks between the two sides were called off.
Leo Varadkar has said he believes a Brexit deal is still possible, but that the PM's current proposals do not "form the basis for deeper negotiations".
Nevertheless, Labour MP for Wigan Lisa Nandy advised the programme: 'The truth is we're additional away from a deal than we had been two months in the past and I can't see this getting wherever'.