The PM marked the historic step by drinking English sparkling wine with his team, including chief adviser Dominic Cummings, who is said to have been close to tears as he was hailed for his crucial role. 

However, Mr Johnson had to count down to the crucial moment at 11pm himself after the TV feed to the light show outside the building failed with just seconds to go.

He is understood to have banged a small gong to signal that the UK's departure from the bloc had officially taken place.

The cast list for the reception included Cabinet ministers, No10 staff and officials who had been part of the huge effort to force through Brexit. Mr Johnson's partner Carrie Symonds tweeted a picture of their dog Dilyn dressed up in a Union flag coat.

They were served a selection of patriotic canapes including fillet of lamb on toast, Shropshire blue cheese, beef and Yorkshire pudding with horseradish sauce, mushrooms tarts and roast chicken skewers. 

Meanwhile, outside a countdown was projected on to the famous No10 black door from 10pm  - and a pre-recorded address to the nation by Mr Johnson was broadcast.  

Within the walls, the premier voiced gratitude to everyone who had helped secure the huge change for the country.

'This is a fantastic moment in the life of our country. There are very few moments in our lives that really can be called an historic turning point, and this is it,' he said,

'This is not the end, as some people would say. It's not even the beginning of the end. It's not the half of the middle. This is the end of the beginning.

'This is the start of something fantastic and different. And this is our chance to do something different and fantastic with our wonderful country.'

Mr Johnson told the audience he knew many of them did not vote Leave in the 2016 referendum, but he 'didn't care'.

'We did it, we absolutely did it. But much more important than that, this is a turning point for the life of our nation and a genuine chance for change and renewal,' he said.

'It is the moment where we have to answer the demand of those who voted for Brexit in 2016.'

Mr Johnson said the British public were the 'real heroes of this story'.

'If you think what happened, in 2016 they were given a choice - and they voted very substantially to leave,' he said. 

'The people of this country voted to leave despite everything they were told by the CBI and the BBC.

'But the people of this country in their bravery, in their absolutely brilliant, logical, divination of the truth, they voted to leave in spite of all of the threats of punishment that they heard.' 

The PM did nod to the scale of the task that now faces the government to thrash out trade terms with the EU and overhaul the UK's services, saying they had to move 'very fast'.

'I am a Conservative and we are going to deliver a fantastic agenda to take this country forward. And time is marching and we've got to go very, very fast to get it all done.'

He also paid tribute to Mr Cummings, pointing out that he had been the architect of the Vote Leave campaign and drove the Tory election strategy that resulted in a stunning 80-strong majority last month. 

'It was he, I seem to remember, who came up with the famous phrase that we should 'take back control'.

'It was also Dom that came up with the other three word epigram, that the policy of the government should be to ''get Brexit done''.

'And I want you to remember that you were here tonight, after 11 oclock, when finally, we got Brexit done.' 

Mr Cummings was said to be close to tears as he rose to make a speech, and merely said: 'Lots of people in this room know what happened. Thank you.' 

Compiled by Olalekan Adeleye

MailOnline