By Jemima Kelly

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 Article 50, which formally starts the exit process from the bloc, would be triggered before the next election.

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.

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 also said Article 50 of the Lisbon Treaty, which will begin Britain's formal divorce from the EU, 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.

(This refiled version of the story fixes typo in sixth paragraph)

(Additional reporting by Paul Sandle, editing by Louise Heavens)