British MPs on Monday debated a petition signed by more than 4.1 million people demanding a second referendum on European Union membership.

Britain's government has ruled out a second referendum and says it is preparing to trigger the formal divorce proceedings that would eventually take Britain out of the club it joined in 1973.

In the days following the Brexit referendum result, millions of people signed the petition calling for a second vote on membership.

"The Brexiteers wanted out of Europe but they had no plan for the day after or any other day in the future," said Ian Blackford, a Scottish National Party MP who supported the motion for the debate, in Parliament's second debating chamber, which does not have the power to change the law.

In the June 23 vote, 51.9 per cent, or 17.4 million people, voted to leave the EU while 48.1 per cent, or 16.1 million people, voted to stay.

"Brexit must mean Brexit and it is up to every red-blooded democrat, no matter which side they were on before the result was known, to accept the clear electoral verdict and to pull together to deliver it as best we can," said John Penrose, a Conservative Party MP who opposed the motion.

David Lammy, a Labour MP, said during the debate that the meaning of Brexit was unclear, as were what the terms would be for Britain to have access to the European single market.

Political and financial turmoil

The Brexit result, which historians say compares to the 1991 fall of the Soviet Union in its significance, unleashed immediate political and financial market turmoil in Britain.

The vote has also raised questions about the future of Britain and post-Second World War European integration, though the economic impact has been less negative than was predicted by remain campaigners.

Prime Minister Theresa May, who did not support leaving, says Brexit means Brexit and the vote will be respected.

But at least seven lawsuits have been brought to force the government to accept that Parliament should decide whether Britain should trigger Article 50 of the Lisbon Treaty, the formal exit process, rather than the prime minister.

Immigration concerns

Meanwhile, immigration seems to be one big issue in preparing for Brexit.

The chief of Britain's new Brexit Department said Monday the government will not be rushed as it develops detailed plans for leaving the EU, as May backed away from proposals to use a point-based system to manage immigration.

David Davis told Parliament his new ministry already has 180 staffers backed by 120 more working in Brussels.

David Davis, chief of Britain's new Brexit department, is suitably vague in the Commons 0:34

In China for the G20 summit that ended Monday, May said she is not in favour of a points-based immigration system backed by Foreign Secretary Boris Johnson and Nigel Farage, key leaders of the pro-Brexit campaign.

She said the Australian-style system would not give Britain sufficient control of who enters the country, as sought by Brexit backers.

Farage, who has stepped down as leader of the pro-Brexit U.K. Independence Party, accused May of backsliding.

The government has not spelled out how it plans to control immigration once it leaves the 28-nation EU bloc, but May has said curtailing immigration is a top priority.