Image copyright Reuters Image caption EU chief negotiator Michel Barnier (r) sat with President of the European Commission Jean-Claude Juncker

EU leaders have pulled apart the UK's Brexit proposals, accusing Boris Johnson of putting forward untested ideas to solve the Irish border crisis.

Chief negotiator Michel Barnier said the EU needed workable solutions "today not tomorrow".

European Commission President Jean-Claude Juncker told MEPs that while he would "not exclude" a deal in the coming days, progress had been limited.

Mr Johnson has said he remains "cautiously optimistic" about a deal.

He will meet his Irish counterpart, Leo Varadkar, on Thursday to try and break the deadlock, while continuing to insist the UK will leave on 31 October with or without an agreement.

In Westminster, meanwhile, a group of Conservative MPs has been demanding assurances from the PM that he will not take the party into the next general election - whenever it comes - on a straightforward promise to leave with no deal.

And earlier, it emerged MPs would be called to Parliament for a special Saturday sitting on 19 October - the day after a crunch EU summit, which is seen as the last chance for a deal ahead of the Halloween deadline.

The UK put forward fresh proposals for a Brexit deal last week, but so far the reaction from the EU has not been encouraging.

Updating MEPs on the state of talks, Mr Barnier said he believed "with goodwill" on both sides there could be an agreement in the run-up to the summit.

But he said "to put things very frankly and to try to be objective, we are not really in a position where we are able to find an agreement".

As it stood, he said, the UK was proposing replacing an "operable, practical and legal solution" to avoid a hard Irish border with "one that is simply a temporary solution".

Media playback is unsupported on your device Media caption Confused by Brexit jargon? Reality Check unpacks the basics

Mr Barnier said the UK's suggested alternative to the Irish backstop - which would see customs checks conducted away from the border at business premises or electronically - "had not been tested" and was "largely based" on exemptions for small businesses and technology that "has yet to be developed".

"We need operational real controls, credible controls, we are talking about the credibility of the single market here - its credulity to consumers, to companies, and to third counties that we have agreements with."

Mr Barnier also questioned the viability of the UK's proposals to give the Northern Ireland Assembly a veto over whether it aligned with EU single market rules for goods from 2021 onwards and whether to diverge from them in the future.

However, he did confirm the two sides were looking at "a more important role" for the Northern Irish political institutions.

Merkel call

Under Mr Johnson's proposals, which he calls a "broad landing zone" for a new deal with the EU:

Northern Ireland would leave the EU's customs union alongside the rest of the UK, at the start of 2021

But Northern Ireland would continue to apply EU legislation relating to agricultural and other products, if the Northern Ireland Assembly approves

This arrangement could, in theory, continue indefinitely, but the consent of Northern Ireland's politicians would have to be sought every four years

Customs checks on goods traded between the UK and EU would be "decentralised", with only a "very small number" of physical checks

Mr Juncker, meanwhile, took a swipe at the UK in the wake of a political row over the details of Tuesday's phone call between Mr Johnson and German Chancellor Angela Merkel.

Following the call, a No 10 source claimed the German leader had said a deal based on the UK's proposals was "overwhelmingly unlikely" and made new demands which made an agreement "essentially impossible".

"We remain in discussion with the UK," Mr Juncker said. "Personally I don't exclude a deal. I do not accept this blame game that started in London."

'Insulted'

During a sometimes bad-tempered debate in the European Parliament, former Belgian prime minister Guy Verhofstadt, accused Mr Johnson of treating those seeking to prevent a no-deal Brexit as "traitors, collaborators and surrenderers".

"The reason this is happening is very simple. It is a blame game. A blame game against everybody - against the EU, against Ireland, against Mrs Merkel, against the British judicial system, against Labour, against the Lib Dems, even against Mrs May," he said.

"The only person who is not being blamed is Mr Johnson apparently. All the rest are part of the problem."

Image copyright AFP Image caption The government has said there will be few physical customs checks

Lib Dem MEP Jane Brophy urged the EU to give the UK as long an extension as possible to allow time for a general election and a referendum.

But Brexit Party leader Nigel Farage suggested Brussels was no longer negotiating in "good faith" and the UK was fed up with being "talked down to and insulted" by EU leaders.

"You are not looking for solutions. You are looking to put obstacles in our way."

No-deal disquiet

Mr Farage also suggested a no-deal Brexit would be a "winning ticket" at a future general election - a prospect which has reportedly caused some disquiet among Conservative MPs.

At a meeting on Wednesday afternoon with a group of One Nation Tories - led by ex-minister Damian Green - the PM was told that dozens of his MPs would not be willing to support a straightforward manifesto promise to leave without a deal if there was a snap election before the end of the year.

Mr Johnson sought to reassure them he was still very much focused on getting a deal.

But the BBC's Laura Kuenssberg said while no decision had been taken, she understood a future manifesto could include a promise to leave with an agreement if possible, alongside a vow to leave anyway "within days or weeks" if the Tories won a Commons majority and there was no chance of a deal.

The prime minister has said he is determined the UK will leave the EU on 31 October, despite legislation, known as the Benn Act, which requires him to write to Brussels requesting a further delay if a deal is not signed off by Parliament by 19 October - or unless MPs agree to a no-deal Brexit.

Scottish judges decided on Wednesday to delay a decision on whether to sign the letter if Mr Johnson refused to do so, saying instead they would wait until the political debate had "played out".

Elsewhere, there was anger among some Brexiteers after European Parliament President David Sassoli met Commons Speaker John Bercow in London.

A statement after the meeting from Mr Sassoli said they both "fully agreed on the important role that our parliaments play in the Brexit process" and the European institution would support any request from the UK for an extension.

Mr Farage said it was "disgraceful" the pair had "agreed to work to prevent a no-deal Brexit".

Conservative MP Marcus Fysh said it was "so far beyond his (Mr Bercow's) constitutional role" and accused him of "colluding with a foreign power".