Increasing numbers of voters are losing faith in Boris Johnson’s leadership, while only one in five people believe he can secure a Brexit agreement before the Halloween deadline, a poll has found.

The exclusive survey for The Independent found 54 per cent were dissatisfied with the prime minister’s performance following a torrid few weeks marred by a string of Commons defeats and the Supreme Court’s ruling that his decision to prorogue parliament was unlawful.

The poll by BMG Research revealed a surge in dissatisfaction with Mr Johnson since September (45 per cent) and August (41 per cent), shortly after he took office.

However, core support for his leadership hovered around the same mark, at 35 per cent this month, 39 per cent in September and 35 per cent in August.

As the prime minister makes a last-ditch push for a Brexit deal, the majority of voters (58 per cent) remain sceptical that he can reach an agreement with Brussels before the 31 October deadline, with 22 per cent unsure and only 20 per cent believing he can deliver.

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Mr Johnson has maintained his “do or die” pledge to deliver Brexit by 31 October – despite a backbench law compelling him to ask for an extension if he has not agreed a deal by 19 October.

But the EU dealt a blow to his plans by snubbing talks this weekend after agreeing that his new proposals to replace the Irish border backstop “do not provide a basis for concluding an agreement”.

Separately, the poll found 34 per cent of voters think Mr Johnson is capable of managing Brexit and 46 per cent do not, with about one in five people declaring themselves unsure.

Robert Struthers, head of polling at BMG, said: “As we get closer to the 31 October deadline, our polling is clear that a sizeable majority of the public are sceptical about the prospects of the government striking a deal with their European counterparts.

“What is also striking is the extent to which Remain voters are much more likely than average to say a deal cannot be done. Some 72 per cent of Remain voters hold this view, which compares to just 12 per cent who think a deal will be agreed in time.

“That being said, despite the deadline being a matter of weeks away, these numbers are largely consistent with our figures for this question from September and August. So, whilst levels of scepticism are high, there is no evidence to suggest that they have increased over the last two months.”

Downing Street is understood to be considering a diplomatic push with senior EU figures in the coming days, as Mr Johnson tries to sell his Brexit plan both at home and abroad.

He spoke to Dutch prime minister Mark Rutte on Saturday, but Mr Rutte made it clear that “important questions remain” over the plans.

Mr Johnson’s chief Brexit negotiator, David Frost, will be in Brussels next week to continue talks, but no decision has been made over whether the prime minister will travel out to join him.

In a glimmer of hope for Mr Johnson, ex-minister Margot James suggested his proposals could win the backing of the 21 exiled Tory MPs, who were expelled from the party for supporting a backbench bid to take no deal off the table.

Ms James told BBC Radio 4’s The Week in Westminster: “If the prime minister can get EU and Irish agreement then I think that we would – we’ve all got reservations – but we would be prepared to compromise and vote for the deal. Our prime concern really is to avoid Britain leaving without a deal.”

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Tory Brexiteer Paul Scully also said there was a “lot of sympathy” among Conservative Eurosceptics to get the deal through the Commons, adding: “It does most of the things that Leavers asked of our government to sort out.”

But Labour’s Lisa Nandy, who represents Leave-voting Wigan, said: “The truth is we’re further away from a deal than we were two months ago and I can’t see this getting anywhere.”

On Tuesday, Mr Johnson will ask the Queen to prorogue parliament for several days ahead of a Queen’s Speech on 14 October, when the government will lay out out its legislative programme.

Crunch time will come for the prime minister around the European Council summit on 17-18 October, where he must secure agreement from the EU if a deal is to be rubber-stamped in time for Brexit day.

If not, he could be forced to demand a delay, a move which could derail his premiership.