British Brexit secretary David Davis (L) and European Union (EU) chief negotiator Michel Barnier attend a joint press briefing in Brussels, Belgium, Aug 31, 2017. [Photo/Xinhua]

LONDON - As MPs in the House of Commons prepare to hold their first votes on a crucial Brexit Bill, two leading law experts warned Sunday of the high risks to Britain's future.

European and British law experts, Professor Michael Dougan and Dr Michael Gordon from the University of Liverpool, have both highlighted the potential hurdles for the European Union Withdrawal Bill, known as the Repeal Bill.

On Monday, MPs will vote on a number of amendments to a bill that is aimed at transferring more than 40 years of EU law into British law.

The main opposition Labor Party plans to oppose the bill, describing it as a power grab by the governing Conservatives.

With fears that a number of pro-European Conservatives may vote against the bill, all eyes will focus on how Prime Minister Theresa May, heading a minority government, handles the situation.

Thousands of people campaigning for Britain to remain in the EU staged a march through London on Saturday to the Parliament Square.

In the world of academia, experts have been mulling the possible impact and repercussions of the repeal bill.

In a joint briefing paper, Dougan and Gordon say the Repeal Bill could be seen as the source of significant problems.

They say: "The scheme set out in the bill is based on an extensive centralization of power as well as a massive delegation of power, to the British government.

"The bill's approach generates considerable costs and risks for the relationships between the British government and those in Scotland, Wales and Northern Ireland. It has a clear potential to destabilize key constitutional relationships, or infringe key constitutional values, not least those relating to democracy and legitimacy.

"Some of those risks could well be mitigated, but it is difficult to envisage any fundamentally different approach to that proposed by the government. As such, the bill demonstrates the inevitable and high price to be paid for the government's strategic choices.

"Protecting our economy and society from significant disruption and uncertainty will require us to sacrifice other constitutional values of at least equal (if not greater) importance," added Dougan and Gordon.

In another major intervention Sunday, former Labor prime minister Tony Blair put forward a plan he said would enable Britain to control immigration while staying as a member of the EU.

Writing in the Sunday Times newspaper, Blair put his name to a report calling on the British government to force EU migrants coming to Britain to register on arrival so they can be counted in and out of Britain. Those who failed to register would be banned from renting a home, opening a bank account or claiming benefits.

The Sunday Times described Blair's move as "an explosive intervention that will electrify the Brexit debate". The former prime minister says proper immigration controls would make it possible to take back control of Britain's borders without leaving the EU.

The report, adds the newspaper, will make uncomfortable reading for Prime Minister May.

Meanwhile, the Sunday Telegraph says an unrepentant Blair has called on MPs and Conservative ministers on the eve of the Brexit vote to rise up against the government and oppose Brexit, as he hinted at plans for a new political party to offer a second referendum.

Blair has also called on the Labor party, now led by Jeremy Corbyn, to reverse its position on Brexit and oppose leaving altogether.

Labor say they support the Brexit referendum decision but they favor Britain continuing with a European single market and customs union trading arrangement with Brussels.