THERESA May’s fragile grip on power has been dealt a further blow after her offer to other parties to co-operate on major issues like Brexit was rebuffed by political opponents and denounced by allies.

In a speech in London today, the Prime Minister will urge her other parties to "contribute and not just criticise" on policy-making as she acknowledges that, post the General Election when the Conservatives lost their majority, the UK Government is now working in a “new context”.

Damien Green, the first secretary of state, argued that the change in Mrs May's style of government was a "grown-up way of doing politics".

But the PM’s offer was firmly rejected by Jeremy Corbyn, who, during Commons exchanges on last week’s G20 summit, said it showed the Tory Government had “run out of steam”.

Mockingly, he told Mrs May he was happy to give her a copy of the Labour manifesto as she had run out of ideas, adding: "Or better still,[call] an early election so the people of this country can decide."

Ian Blackford, the SNP leader, rejected her offer of co-operation by launching a double attack.

On the G20, he said the UK was “now floundering around on a global stage desperately trying to make friends” as he said a “disastrous and unpredictable alliance” on trade had been formed with US President Donald Trump.

And in another broadside, the Highland MP accused the PM of having displayed "staggering hypocrisy" by asking other nations to tackle terrorist financing while she sat on an unpublished UK terror funding report.

The Tory leader’s own colleagues were also critical of her attempt to reach out to Mr Corbyn and other opponents.

Sir Desmond Swayne, the former international development minister, questioned the move, saying: “On the new love-fest with members on the opposition benches, given the record of the Leader of the Opposition on the Counter-Terrorism and Security Act 2015, does the Prime Minister possess a very long spoon?”

His Tory colleague Sir Edward Leigh noted how their party leader was “now open to ideas from a man who tried to remove her from office”.

Outside the chamber, one former minister complained: “It is one thing to be weak it is another thing to advertise your weakness.”

Another said her departure from No 10 was “now only a matter of time,” pointing out how Mrs May was expected to face Tory MPs at the 1922 backbench committee later this week.

At the weekend, Andrew Mitchell, the former Conservative cabinet minister, was said to have told a private dinner that the PM was "dead in the water" and had lost all authority.

This morning in her keynote speech, Mrs May will say: “I say to the other parties in the House of Commons...come forward with your own views and ideas about how we can tackle these challenges as a country.

“We may not agree on everything but through debate and discussion – the hallmarks of our parliamentary democracy – ideas can be clarified and improved and a better way forward found. It is in that spirit that we will take this agenda forward in the months ahead.”

The PM will note that “this new context presents us as a government with a wider choice; at this critical time in our history, we can either be timid or we can be bold. We can play it safe or we can strike out with renewed courage and vigour, making the case for our ideas and values and challenging our opponents to contribute, not just criticise”.

She will add: “This country needs a government that is prepared to take the bold action necessary to secure a better future for Britain and we are determined to be that government.

“In everything we do, we will act with an unshakeable sense of purpose to build the better, fairer Britain which we all want to see."

Earlier, Mrs May’s Brexit strategy hit turbulence from Brussels after Guy Verhofstadt, the EU’s chief negotiator, rejected her offer on citizens' rights, claiming it was casting a "dark cloud" over people's status.

In a joint article with a cross-party group of senior MEPs, the former Belgian premier said the PM's plan was a "damp squib," which carried a risk of creating "second-class citizenship".

He claimed MEPs would block a Brexit deal that did not meet their demands even if it was agreed between the UK Government and EU member states, represented by Michel Barnier, the European Commission chief negotiator.

"At the end, it is the European Parliament who will say yes or no and I can tell you that it will not be a yes if the rights of the European citizens, like also the rights of the UK citizens living on the continent, will be diminished, will be cut off, as it is for the moment," insisted Mr Verhofstadt.

At Westminster, Mrs May suffered another blow after she announced Tory MP Anne Marie Morris was having the party whip removed for using “completely unacceptable” language.

The Leave-supporting Devon MP caused offence after describing the prospect of leaving the European Union with no deal as "the real n***** in the woodpile".

Ms Abbott said her comment was "entirely unintentional", adding: "I apologise unreservedly for any offence caused."

But political opponents denounced her “racist” and “disgusting” language.

The incident means Mrs May’s tally of Conservative MPs in the Commons is reduced further, making her even more reliant on the votes of Northern Ireland’s Democratic Unionists.