BERLIN (Reuters) - Making changes to the contentious Irish backstop is the only way to secure a Brexit agreement, British Foreign Secretary Jeremy Hunt said before Prime Minister Theresa May heads to Brussels on Wednesday to try to salvage her deal.

The key sticking point in Brexit negotiations is the so-called backstop, an insurance policy to prevent the return of extensive checks on the sensitive border between EU member Ireland and the British province of Northern Ireland.

Hunt called for “a simple and important change” to the backstop, “but one that guarantees the future of the Belfast Good Friday peace agreement,” adding: “If we can make that change, we are confident we can get this deal through.”

“This is really the only way through the current situation,” Hunt said during a question and answer session after giving a speech to the Konrad Adenauer Stiftung in Berlin.

May makes another trip to Brussels on Wednesday, hoping European Commission chief Jean-Claude Juncker may prove more yielding than of late to salvage her Brexit deal.

Hunt said the “critical thing” is that the British Attorney, General Geoffrey Cox, needs to be able to change his advice to parliament, which “currently says it is possible, if not likely, that Britain could under the current backstop arrangements be trapped in the customs union for ever against its will”.

“That is the issue parliamentarians have difficulty with.”

Calling for “generous and far sighted leadership”, Hunt said: “We must all do all that we can to ensure that a deal is reached.”

Hunt said “a smooth and orderly exit is profoundly necessary”, but saw little point in extending negotiations beyond Britain’s planned exit from the EU on March 29.

“The issue about an extension is whether that really solves anything,” he said. “The last thing people in the UK and Europe want is Brexit paralysis. I think people want to move on.”