The Institute of Government (IFG), a London-based charity, has issued an 18-page report saying that the legal demands of withdrawing from the European Union once Article 50 has been triggered on March 29 with mean domestic issued will very likely be overlooked.
IFG’s research director Dr Hannah White told BBC Radio Four’s Today programme: “The estimates we have heard are something between 10 and 15 Bills required in the next two parliamentary sessions. Normally, there are about 20 in a Queen’s Speech.
“So, that’s roughly the capacity that there is in government to draft these Bills and, in terms of parliamentary time, to pass them.
“So, that takes a big chunk out of the Government’s capacity to legislate. And its other priorities, its domestic priorities, will take a hit in the next couple of sessions.
“There will have to be some really tight prioritisation in Government to work out what else is going to be done aside from the Brexit legislation.”
Dr White said the Bills, dealing with issues such as immigration procedures, agriculture and customs, would be on top of the Great Repeal Bill, which will incorporate EU law into British law.
Ministers have been tackled by peers over the “huge volume” of new laws that will be demanded by Brexit and the question of whether it will leave time for any other legislation to be carried through.
But the Government frontbench refused to be drawn on details, instead telling members of the House of Lords that “good things come to those who wait”.
For the opposition, Baroness Hayter of Kentish Town pressed the Government over how it planned to deal with the increased legislative workload as a result of leaving he EU.
Brexit minister Lord Bridges of Headley said in response: “I am not going to go into that much detail now. Good things come to those who wait.
“A lot of thought has been going into… not just the amount of legislation that will be required be it primary or secondary but also the need to make sure that we get those statutes onto the statute book in time whilst balancing the need for effective and proper scrutiny.”
The minister was pressed again later by Labour peer Lord Foulkes of Cumnock, who said: “In view of the huge volume of legislation in order to implement Brexit, will there be any time for any other legislation?”
Lord Bridges drew groans when he told peers: “We have a very full action-packed manifesto, which we are determined to see through as much as possible.
“Sorry, that’s what happens when you get elected. You get elected on a manifesto and then you see it through.”
During questions in the Lords, the minister was also picked up on an earlier response in which he was asked if the Article 50 process was reversible and he had said it could not be revoked.
Labour peer Lord Campbell-Savours pointed out these were “two completely different issues”.
Lord Bridges said: “We have said regardless of the legal position we do not intend to revoke our notice to withdraw.”
The report comes as Prime Minister Theresa May has embarked on her tour of the United Kingdom, which she kicked off in Wales.
The IFG report said that “there has been a complete lack of clarity about the role that the devolved legislatures will play in legislating for Brexit”.
It added: “The attitude that the Scottish National Party (SNP) takes to the passage of Brexit-related legislation in Westminster could affect the smoothness with which that legislation passes through Parliament if they join forces with the Labour Party and Conservative rebels.”