Watch the moment MPs laugh in the face of Theresa May

This was the moment MPs erupted into furious laughter at Theresa May.

The Prime Minister was delivering her historic speech on Wednesday officially signalling the beginning of the process which will see Britain leave the European Union.

Her words came at the same time as British officials handed a letter to their European counterparts in Brussels, triggering the process to start the UK’s exit.

But any attempts by the PM to keep the day’s events on a sombre tone were lost after Theresa May told a raucous House of Commons: “Perhaps now, more than ever, the world needs the liberal democratic values of Europe,” she said, seeking sought to explain why Britain is leaving.

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This was too much for the opposition benches, mostly those who voted to remain in the EU, to ignore.

Donald Tusk holds up the letter from the British govt triggering its exit from the EU (Rex)

At first there was sporadic laughter, but this quickly gave way to long and sustained mocking of the PM’s words.

Mrs May tried to continue but the barrage of hysteria from those opposite meant her words were drowned out before she could go any further.

The laughter continued for half-a-minute or so as the PM, looking uncomfortable, waited for it to subside.

She was eventually able to continue.

While she was speaking, in Brussels Sir Tim Barrow entered the room of European Council president Donald Tusk armed with a white envelope.

PM Theresa May on her way to the House of Commons to deliver her historic address (Rex)

The pair spoke in hushed tones surrounded by two Union Flags and two European Union flags in a room on the 11th floor of the Europa building.

Then, as cameras rapidly fired away to capture the historic moment, Sir Tim passed the letter to Mr Tusk, confirming the intended departure.

The pair shook hands and left, Mr Tusk to an office on the left and Sir Tim down a corridor to the right.

The formal triggering of Article 50 had begun and the UK was officially on a course to leave the European Union after 44 years.