Up to 15 new bills could be needed to deliver Brexit, placing a "huge burden" on Parliament and Government and leaving little time for any other legislation, a think tank has warned.

The Institute for Government, an independent group, said in a report called Legislating Brexit that the extra 15 measures would cover areas including immigration, agriculture and customs.

They would be in addition to the Great Repeal bill, which will end EU legal authority in the country by scrapping the 1972 European Communities Act.

The 18-page report says the task will leave little time for anything else, pointing out that the Queen's Speech typically announces about 20 new bills.

"Brexit will place a huge burden on both Parliament and Government departments", it said.


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"Considerable time and resource will be soaked up and there will be precious little space left in the legislative programme for other legislation that departments might have wanted to see pass."

The report was published as Theresa May visits Wales as part of the Government's effort to convince the devolved nations that their input will help shape its Brexit negotiations.

A spokesman for the Prime Minister said the trip to Swansea was part of an "ongoing engagement" with the nations, and that Mrs May will be "listening to people from right across the nation as we prepare to leave the EU".

The report by the IFG said that "there has been a complete lack of clarity about the role that the devolved legislatures will play in legislating for Brexit".

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"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," it added.

It called on the Government to "make clear at the earliest opportunity what role it envisages for the devolved legislatures".

Mrs May plans to trigger Article 50 of the Lisbon Treaty, which formally starts divorce procedures, by the end of the month.