The devolution settlement is not fit for purpose post-Brexit, according to a new report from an independent think tank.

The Institute for Government (IoG) report concludes the arrangements of the late 1990s were designed to function within membership of the EU.

As the UK Government remains at loggerheads with the Scottish and Welsh administrations over the details of the UK’s withdrawal, the IoG argues a new, closer working arrangement must be found.

Recommendations include an urgent review of the Joint Ministerial Committee (JMC) between the governments with new dispute-settling processes, Westminster committees holding joint evidence sessions with the parliaments and assemblies of the devolved nations and a “four nation by default” set-up of any new public bodies after Brexit.

IoG Brexit programme director Jill Rutter said an overhaul was needed.

She said: “The past year has shown the strain leaving the EU is placing on devolution arrangements designed on the assumption of UK membership.

“It is time for an overhaul. It is in the interests not only of the UK government, but also the devolved governments, to develop firm foundations for future joint working – to promote collaboration and innovation.

“Only then will we have the right environment, agriculture and fisheries policies for the whole country after Brexit.”

A UK Government spokeswoman said a great deal of work had already been undertaken to “strengthen our relationships with the devolved governments as we prepare to leave the EU”.

“The UK Government will work in collaboration with the devolved administrations to review our structures and make sure they are fit for purpose in light of our exit from the EU.”

A Scottish Government spokesman said the report endorsed the view the UK should not impose its will on devolved governments.

“Our position is clear,” he said. “The devolution settlement must be respected.”