MPS have demanded the publication of a Union-boosting blueprint that has spent six months under wraps.

Boris Johnson ordered former Scotland Office minister Lord Andrew Dunlop to work on a plan to ensure government structures are working to “strengthen the working of the Union” last summer.

The result, called the Dunlop Report, was placed on the Prime Minister’s desk in December – and has been kept secret ever since.

Now MPs have urged the government to publish the results – and open them to scrutiny.

The cross-party Public Administration and Constitutional Affairs Committee (PACAC) says the coronavirus pandemic and impending Brexit “raise serious questions about the effectiveness” of how Westminster and devolved governments work together on major issues effecting all of the UK.

And its Tory chairman William Wragg MP has written to Cabinet Office minister Michael Gove urging the government to reveal the results “immediately”. He said: “The emerging tensions between the UK and devolved governments over the response to Covid-19 response, and EU exit arrangements, raise serious questions about the effectiveness of existing mechanisms for consulting and co-ordinating on policy.

“The Dunlop Report may teach us valuable lessons and improve how we develop ongoing strategies to mitigate the serious consequences of the pandemic and is important in helping to develop a better understanding of how practise needs to change to fit the UK’s current constitutional arrangements.

“The committee urges the government to publish the report immediately, and indicate how it intends to take its findings forward to improve how the UK Government works with its counterparts in Northern Ireland, Scotland and Wales.”

The independent review was ordered “to consider whether UK Government structures are configured in such a way as to strengthen the working of the Union, and to recommend changes where appropriate”. Dunlop was told to “take into account” the need to “respect and support the current devolution settlements”.

In March, Cabinet Office Minister Mark Sedwill told PACAC the government does intend to publish the report.

Earlier this week Michael Russell, Scotland’s Constitution, Europe and External Affairs Secretary, told the committee he’d “almost forgotten it existed” and said the Joint Ministerial Council supposed to allow administrations to work together on an equal footing was “bust”.

Last year the Scottish Affairs Committee called for that to be strengthened due to “deteriorating levels of trust” between London and Edinburgh.

The National asked the Cabinet Office when the report will be published – and why it hasn’t happened yet. A spokesperson replied: “The government is grateful for the work that Lord Dunlop has undertaken and is carefully considering his report.”

SNP shadow Scotland secretary Mhairi Black said: “It’s an apt metaphor that the Conservative and Unionist Party has allowed a review into the Union to gather dust in Whitehall. Any pretence that Scotland will ever be treated as an equal partner in the UK has long gone.

“It’s little wonder that as the Tories continue to disregard the devolved governments, support for Scottish independence continues to grow – with polls showing majority support for a second independence referendum.

“People in Scotland deserve the choice of a better future than the broken Brexit Britain on offer from Westminster.”