The Netherlands' prime minister has dealt a blow to Boris Johnson's Brexit plan as he said the EU will not accept any customs border in Ireland.

Mark Rutte told Mr Johnson over the phone 'important questions remain about the British proposals' put forward earlier this week.

However he struck a hopeful tone when he failed to dismiss the prospect of a deal by the upcoming EU summit.

He added: 'There is a lot of work to be done ahead of [an EU summit] on October 17-18.'

It comes after Brussels declined Mr Johnson's request for negotiations to continue over the weekend.

Now diplomats believe any chance of a Brexit deal before October 31 has been scuppered - with an extension the most likely outcome.

Relations were already at a low after Britain's Brexit adviser David Frost told the EU yesterday Britain would not make any 'fundamental changes unless we are in a give-and-take relationship,' an EU official told the FT.

Mark Rutte (pictured in The Hague on Friday) told Mr Johnson over the phone 'important questions remain about the British proposals' put forward earlier this week

Now diplomats believe any chance of a Brexit deal before October 31 has been scuppered - with an extension the most likely outcome. Pictured: Mr Rutte also tweeted about the phone call today

The EU said Mr Johnson's plans to avoid a hard border on the island of Ireland and replace the backstop need to change.

The proposal for a 14-month transition period for customs checks on the island is not acceptable, Brussels said.

Mr Frost said the UK needed to limit the role of the European Court of Justice in pushing through a post-Brexit deal, ditch EU state aid rules for Northern Ireland and called for access to EU goods databases even after Brexit.

It comes after Brussels declined Mr Johnson's (pictured) request for negotiations to continue over the weekend

But Brussels rejected all of these.

An EU diplomat told the FT: 'We are not in a position to engage with these demands.'

Mr Johnson will try again on Monday as he returns to Brussels, but faces an uphill battle as officials said the EU would not enter intensive 'tunnel' negotiations before the October summit.

A British official said: 'We want a deal and talks continue on Monday on the basis of our offer.'

Discussions between the UK and EU have not taken place this weekend as anticipated.

Talks between the two sides were thought likely to continue on Saturday after the Prime Minister set out his plan to replace the controversial Irish backstop.

But the European Commission said EU member states had agreed the proposals 'do not provide a basis for concluding an agreement'.

A spokesman said discussions between the two sides would not take place this weekend and instead the UK would be given 'another opportunity to present its proposals in detail' on Monday.

'Michel Barnier debriefed COREPER (The Permanent Representatives Committee) yesterday, where member states agreed that the UK proposals do not provide a basis for concluding an agreement,' the spokesman added.

Mr Frost has been in Brussels for technical talks with officials.

But Mr Johnson's proposals won support from the likes of Margot James - who was one of the 21 Tory rebels expelled from the party last month - and Paul Scully of the European Research Group of Tory Eurosceptics.

Ms James told BBC Radio 4's The Week In Westminster she thought she and the other sacked rebels would be able to support the PM's proposals.

'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.'

Mr Scully said there was a 'lot of sympathy' among members of the ERG 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 told the programme: 'The truth is we're further away from a deal than we were two months ago and I can't see this getting anywhere.'

The move came after Mr Johnson insisted on Friday that he would not delay Brexit despite his lawyers saying he will comply with a law calling for the October 31 exit date to be postponed if there is no deal.

The Prime Minister accepted he must send a letter requesting a delay to Brexit beyond the Halloween deadline if no deal is agreed with Parliament by October 19, Scotland's highest civil court heard.

But the PM later said the options facing the country were his proposed new Brexit deal or leaving without an agreement, 'but no delay'.

The Prime Minister has previously said 'we will obey the law' but will also leave on October 31 in any circumstance, without specifying how he would achieve the apparently contradictory goals - fuelling speculation that he had identified a loophole to get around the Benn Act.

But the PM later said the options facing the country were his proposed new Brexit deal or leaving without an agreement, 'but no delay'

The Telegraph, citing EU sources, said senior ministers had reached out to the Hungarian government for assurances it would veto any request for a delay - seen as one way the PM could comply with the law and deliver Brexit this month.

He has also declared that he would rather be 'dead in a ditch' than ask for a delay.

Any extension to the Article 50 process - the mechanism by which the UK leaves the European Union - would have to be agreed by all 27 other EU leaders.

The legal action - led by businessman Vince Dale, SNP MP Joanna Cherry QC and Jolyon Maugham QC - asked the court to require Mr Johnson to seek an extension to avoid leaving the EU without a deal.

Andrew Webster QC, representing the UK Government, said the documents it has submitted to the court are a 'clear statement' as to what the Prime Minister will do.

He argued there is no need for an order to be made forcing a letter requesting an Article 50 extension to be sent under the terms of the Benn Act, because the court has it on record it will be sent.

Judge Lord Pentland is to announce his decision on Monday.