Boris Johnson called his Brexit plan "a practical compromise that gives ground where necessary"

With the resumption of crunch Brexit talks on Monday looming large, European leaders piled pressure on British Prime Minister Boris Johnson to revise his offer -- and to do so quickly.

On Saturday Johnson started phoning his EU counterparts to sell his proposals for a managed withdrawal from the bloc, after the latest plans were given short shrift by Brussels.

European diplomats say London needs to offer a revised, viable way forward before the end of next week, so that any haggling and legalistic work is done before a crucial EU summit on October 17-18.

That high-stakes European Council meeting will determine whether Britain is headed for an agreement, extension, or potentially disastrous no-deal.

Finnish Prime Minister Antti Rinne -- whose country currently holds the European Union's rotating presidency -- said he had told Johnson it was "important to find a solution within a week" and the British leader "agreed with the timetable".

Dutch Premier Mark Rutte tweeted he had told Johnson "important questions remain about the British proposals" and "there is a lot of work to be done ahead" of the summit.

Johnson was expected to also call the leaders of other EU countries after talks broke up without progress Friday between a top UK Brexit official, David Frost, and the EU team headed by top negotiator Michel Barnier.

"An agreement will be very difficult to reach, but it is still possible," Barnier said on Saturday at an event organised by French newspaper Le Monde.

"We are ready for no-deal, even if we don't desire it," he said. "No-deal will never be the choice of the EU. If it happens, it would be Britain's choice."

The UK had been keen for discussions to continue through the weekend, but they were set to restart on Monday.

A week's window

Johnson's proposals, submitted Wednesday, "do not provide a basis for concluding an agreement," a European Commission spokeswoman underlined on Friday.

The EU refuses to characterise the talks held so far as negotiations, preferring to resurrect a Brexit withdrawal agreement struck with Johnson's predecessor Theresa May that has been rejected three times by British MPs.

The main sticking point is a "backstop" for Northern Ireland that under the May agreement would have seen all the UK, or at least Northern Ireland, remaining in the EU's customs union.

It is meant to guarantee that no border springs up between the British territory and EU member Ireland -- which would threaten the hard-won Good Friday peace accord -- while also maintaining the integrity of the EU's single market.

Britain's current idea for an alternative is for untried technology to remove the need for most but not all border checks, and for EU standards on goods to continue to apply in Northern Ireland to facilitate trade.

This border plan is not acceptable for the EU. It sees the potential for rampant smuggling -- especially as Johnson intends for the rest of the UK to diverge from EU labour, environmental and tax norms to aim for a regulation-lite economy on Europe's doorstep.

Johnson on Saturday called his plan "a practical compromise that gives ground where necessary" but has also previously suggested it was a broad "landing zone" -- which to Brussels suggests he might yet budge on issues it finds unacceptable.

But in identical articles for the Brexit-backing British tabloids the Sunday Express and the Sun on Sunday, Johnson said the bloc now needed to show "its own willingness to do a deal that the UK Parliament can support".

"They should be under no illusions or misapprehensions," he added.

"There will be no more dither or delay. On October 31 we are going to get Brexit done."

Ireland's leader Leo Varadkar said that while Britain's current proposals do not yet "form the basis for deeper negotiations", there is "plenty of time" to put forward alternatives and he was trying to arrange a meeting with Johnson next week, reported Irish broadcaster RTE.

Early UK elections possible

Nor does the EU agree with a proposal giving Northern Ireland's assembly an effective veto over the post-Brexit customs arrangement.

If Johnson does not alter those points, it is hard to see the EU moving talks into the negotiation phase.

Yet if he bends on them, Johnson risks losing tenuous support in the UK parliament to maybe pass a Brexit deal, reliant on 10 Democratic Unionist MPs from Northern Ireland and hard-core Brexit MPs in his Conservative Party.

If thwarted, Johnson's best bet may lie with early elections -- but those could only happen after the date he has said Brexit would happen.

There he also faces a challenge, with the UK parliament having passed a law requiring him to seek a Brexit extension from the EU by October 19 if he has not reached a deal by then.