LONDON (Reuters) - Britain’s vote to leave the European Union must be binding, the chairman of Britain’s ruling Conservative Party said on Sunday, and the exit process will be started before the next general election.

Patrick McLoughlin arrives to attend a cabinet meeting at Number 10 Downing Street in London, Britain February 2, 2016. REUTERS/Stefan Wermuth

Patrick McLoughlin, who was made party chairman by new Prime Minister Theresa May last week, told the BBC’s Marr Show that the vote for Brexit meant Britain must now get control of its own borders and that immigration must be reduced.

Asked about a report in the Observer newspaper that an “emergency brake” on the free movement of people was being discussed, which would allow Britain to keep access to the European single market, McLoughlin said: “Let us see.”

“I’m quite clear that the referendum result is binding on parliament,” he said.

Although May has vowed to press ahead with Brexit, supporters of remaining in the EU contend the referendum result is only advisory.

At least seven lawsuits have been filed arguing that parliament must have the final decision on whether to invoke Article 50 of the Lisbon Treaty to start the two-year countdown to leave the bloc. May has indicated negotiations on an exit could not start this year.

London’s High Court ruled last week that the case would be heard in mid-October and lawyers said it was highly likely it would then be heard by the Supreme Court in mid-December.

The BBC reported on Saturday that days before the June 23 EU referendum, then-Prime Minister David Cameron telephoned German Chancellor Angela Merkel to appeal for concessions on the free movement of people, though the idea was eventually shelved.

Immigration was a core issue in the campaign to leave the bloc, with polls in the run-up to the referendum showing worries about the number of people arriving from the EU swaying the public towards supporting Brexit.

McLoughlin said Article 50 would definitely be triggered before the next national election and that it would be difficult for Britain to have an early election because of its fixed-term parliament system. The next parliamentary vote is due in 2020.

A government lawyer told Britain’s High Court earlier this week that Article 50 would not be invoked this year.