Theresa May says Brexit must go forward. Is she right?

The government argues it has a Royal Prerogative to start negotiations to leave the European Union. But opponents, fueled by a High Court decision, say the government can't act without parliamentary approval. 

Britain’s Prime Minister Theresa May pledged Sunday the government will stay on track with its plans for a full exit from the European Union in an attempt to ease fears an impending parliamentary vote would slow or water down Brexit.

In her first public remarks since the country’s High Court ruled Thursday parliament should vote on the start of negotiations with the EU, Ms. May forewarned her opponents not to forget the results of the June 23 referendum.

“The people made their choice, and did so decisively. It is the responsibility of the government to get on with the job and to carry out their instructions in full,” she wrote in the Sunday Telegraph newspaper. “MPs and peers who reject the referendum result need to accept what the people decided.”

May’s strong words come amid speculation members of parliament, empowered by the High Court ruling, would attempt to delay or stymie a complete Brexit. Opponents of the government argue it lacks a so-called Royal Prerogative to start negotiations without parliamentary approval, and it must disclose its strategy for the negotiations. But May and her supporters including Nigel Farage, who led the Independence Party’s Brexit campaign, have indicated this prerogative stems from the populace, pitting members of parliament and others against much of the country.

“There is a political and wealthy ruling elite who are not prepared to accept the democratic result of the referendum,” said Mr. Farage on BBC’s “Andrew Marr Show” on Sunday. “If the people in this country think that they’re going to be cheated, they’re going to be betrayed, then we will see political anger the likes of which none of us in our lifetimes have ever witnessed in this country.”

The referendum to leave the 28-member bloc of the EU was approved by 52 percent of Britons.

The government has said it would invoke Article 50 of the Lisbon Treaty by the end of March next year, starting the divorce process from the EU.

But in a suit brought by lead claimants Gina Miller, an investment manager, and Deir Dos Santos, a hairdresser, the High Court ruled the government must receive approval from parliament before it invokes the EU article.

The government’s “argument is contrary both to the language used by parliament in the 1972 [European Communities Act], and to the fundamental principles of the sovereignty of parliament and the absence of any entitlement on the part of the crown to change domestic law by the exercise of its prerogative powers," wrote Lord Thomas of Cwmgiedd, the chief justice of the three-judge panel.

The government has appealed the decision, arguing it does have such a prerogative. It has vowed to get the court to overrule the decision next month, according to BBC.

The conflict between those on opposite sides of the Brexit debate is, in part, being fueled by the fact Britain is a nation with no single legal text governing its democracy, writes Bloomberg’s Craig Stirling.

“While such ambiguity has proven a strength during the tests of previous centuries, it has also left institutions from the Bank of England to the judiciary open to scarring from the political momentum created by the June 23 referendum result to leave the EU,” writes Mr. Stirling.

In theory, the court decision could allow parliament to block Brexit because most members supported staying in the EU. But many lawmakers have indicated they would be willing to reverse their positions to come into line with the referendum result.

Still, a faction of Britons have aired complaints against the government appeal and its plan to invoke the negotiation clause. Ms. Miller, the lead claimant of the suit, said the government must answer to parliament because the country is not a “tin-pot dictatorship,” according to BBC. Jeremy Corbyn, leader of the Opposition Labour Party, told the Sunday Mirror a list of demands his party would have for Brexit. The “Brexit bottom line,” he said, would require guarantees for access to the single market for exporters, continued protection of workers’ rights, safeguards for consumers and the environment, and pledges that Britain would make up any loss of EU capital investment.

This report contains material from Reuters. 

Editor's note: A previous version of this article misnamed the court to which the claimants brought suit. The government has appealed the decision to Britain's Supreme Court.