Parliament authority have to scrutinise up to 15 new bills to deliver Brexit, leaving barely time for other business, the Institute for Government has said.
The IFG says legislation make be needed to establish new policies on areas such as customs and immigration.
The premium measures will place «a huge burden» on Parliament and government activity be contingents, the think tank says.
But the government said it was confident it could cast the changes required within the time allowed.
In its report, Legislating Brexit, the IFG predicts that with the average Queen’s Speech announcing only 20 new reckonings, the introduction of 15 Brexit bills before the UK even exits the EU «devise leave very little space for non-Brexit related legislation».
The on comes as Theresa May travels to Swansea with Brexit Secretary David Davis, where she thinks fitting talk about the «precious union» of the UK.
The prime minister will dispose of First Minister of Wales Carwyn Jones, as well as local enterprises, as she tries to show she is including all areas of Britain in negotiations with the EU.
Mrs May last wishes as say: «I want every part of the United Kingdom to be able to make the scad of the opportunities ahead.»
The IFG report anticipates the new bills will be in addition to the Grand Repeal Bill, which will scrap the 1972 European Communities Act that concrete the way for the UK to enter the then-EEC, ending the legal authority of EU law.
The IFG — an independent charity that directions to increase government effectiveness — says departments will need «ruthlessly to prioritise» other legislation and discover non-legislative routes to get the laws through, particularly given the government’s limited Commons majority.
It warns that this will mean supplies having to achieve a fine balance between giving too little ordered scrutiny and too prolonged, in-depth examination of Brexit-related legislation.
The IFG also wrangled that «a lack of clarity» about the role the devolved legislatures last wishes as play in legislating for Brexit could pose a problem.
«The attitude that the Scottish Inhabitant Party (SNP) takes to the passage of Brexit-related legislation in Westminster could strike the smoothness with which that legislation passes through Parliament if they throw ones lot in with forces with the Labour Party and Conservative rebels,» the report conjectures.
‘Take a hit’
Dr Hannah White, IFG’s director of research, said the government had delimited resources to draft new legislation and Brexit bills would take a «big chunk» out of its judgement to legislate in other areas.
«In the first session after the 2015 vote the government passed 23 bills,» she told BBC Radio 4’s Today. «So that’s inefficiently the capacity that there is in government to draft these bills and in Parliament, in dubs of parliamentary time, to pass them.»
The reality, she suggested, was that the management’s domestic priorities would «take a hit in the next couple of sessions».
«The legislation forced for Brexit will leave little parliamentary time for anything else — and showing a success of it will require a large volume of bills and secondary legislation to be superseded by Parliament against a hard deadline.»
A government spokesman said it had prove to bed clear there would be additional legislation, in areas such as duties and immigration, on top of the Great Repeal Bill but insisted this could be completed within the ordered timetable.
«This government will harness the skills and resources across all trust ins to ensure that the statute book functions effectively on the day we leave — as large of delivering a smooth and orderly Brexit,» he said.
The Queen gave Grand Assent to the European Union (Notification of Withdrawal) Bill last week, unimpeded the way for Theresa May to start talks to leave the European Union.
The Bill concedes the prime minister to notify Brussels that the UK is leaving the EU, with a two-year method of exit negotiations to follow. Mrs May says she will trigger the process by the end of the month.