HOLYROOD could have the power to block Theresa May’s main Brexit legislation, it has emerged, as the Prime Minister was forced to abandon large parts of the Tory manifesto to get her programme for government through Westminster.

Brexit dominated the Queen’s Speech with eight out of 27 parliamentary Bills devoted to it, including the main Repeal Bill that revokes the 1972 European Communities Act, which took Britain into the EU.

The bill converts all current EU law into UK law, enabling MPs to discard unwanted aspects.

But Mrs May admitted the Scottish Parliament might be required to sign off on the Brexit legislation.

In the Commons, she told the SNP’s Stewart McDonald: “There is a possibility that a Legislative Consent Motion[LCM] may be required in the Scottish Parliament but that is a matter that is being considered currently between the Westminster and Scottish Governments.”

Her spokesman later explained how the two governments were discussing “complicated legal matters” but said there was not yet a “definitive answer” to the question of whether or not Holyrood had the power to block the Repeal Bill.

Earlier this year, Scottish secretary David Mundell said he believed that it would be the case MSPs would have to vote on a consent motion.

An LCM, also known as a Sewel motion after the Labour peer who oversaw the main devolution act, can be passed by the Scottish Parliament to agree that Westminster can legislate on a devolved issue over which Holyrood normally has legislative authority.

Any blocking of the UK Government’s flagship bill by MSPs would set back its parliamentary timetable and provoke a constitutional crisis between Edinburgh and London.

Earlier this year during the legal battle over Article 50, the UK Supreme Court ruled that the LCM was just a political convention, which could be ignored by Westminster.

But Mr McDonald said if this were to happen, then it would “run contrary to everything Mrs May has said about respecting devolved administrations”.

He claimed the UK Government had “put themselves over a barrel” and could have eased intergovernmental relations by taking seriously the SNP administration’s options paper on Brexit.

“Does it mean we now have got a good deck of cards? Yes it does. Obviously, we want to move forward from a position of strength. Clearly, the Tory Government is in an enormously weak position as far as this is concerned,” he added.

At Holyrood, Michael Russell, the Scottish Government’s Brexit minister, called for the UK Government to share the details of the repeal bill with Scottish ministers “as soon as possible”.

He raised concerns that repatriated powers could first go to Westminster as part of a “transitional arrangement” before discussions with devolved administrations.

“There can be absolutely no question of the UK Government attempting to reserve powers in devolved areas and the Scottish Government would not recommend the Scottish Parliament consents to such proposals,” he declared.

Mr Russell stressed that where it was “sensible or desirable” to introduce a common UK framework to replace that provided by EU law, then this had to be achieved through agreement and negotiation.

“It is deeply concerning that the UK Government seems to intend that repatriated powers in devolved areas like agriculture should go by default to Westminster with no clear recognition of the need for the consent of the Scottish Parliament under the Sewel Convention for such changes. This is clearly unacceptable.”

At Westminster, Kirsty Blackman, the Nationalists’ new deputy leader, warned Mrs May and her colleagues against using Brexit as an “excuse for a Westminster power grab”.

Referring to how Michael Gove, the new Environment Secretary, was due to visit the Royal Highland Show in Edinburgh today, she added that the Scot would have to “explain to the Scottish people why the many powers he promised to Scotland – including over issues like farming, fishing and even immigration – have so far come to nothing and why the Tories are now putting current powers, and the very principles of devolution, under threat”.

Earlier in a rowdy Commons atmosphere, the PM said, post election, the test now was whether or not parties chose to reflect the divisions exposed by the campaign or help the country overcome them.

“With humility and resolve, this Government will seek to do the latter. We will do what is in the national interest and we will work with anyone in any party that is prepared to do the same.”

Jeremy Corbyn insisted Labour was a “government-in-waiting” and accused the Tory administration of having “run out of ideas” after delivering a “threadbare” programme.

Ian Blackford, making his first Commons appearance as SNP leader, said: “Theresa May is in office but clearly not in power; she is a lame-duck prime minister leading a lame-duck Government.”

Following a bruising election which cost the Conservatives their Commons majority, the PM has ditched manifesto plans to scrap universal free school lunches, expand grammar schools and means-test winter fuel payments in England as well as offering a free vote on fox-hunting.

The so-called “dementia tax” proposals for social care reform have been downgraded to “options” in a public consultation.

Speculation that Donald Trump’s state visit to the UK might be cancelled was fuelled by its absence from the Queen’s nine-minute address. But Downing Street said the invitation to the US President still stood and did not feature because a date was yet to be fixed.

Meantime, bills contained in the Queen’s Speech include those to extend the HS2 high-speed rail link to Crewe, permit the development of driverless cars, spaceports and commercial satellites, cut whiplash insurance claims and protect victims of domestic abuse.