Brexit: South Staffordshire MP Gavin Williamson shared cuppa with the PM before he told the Queen of resignation

Mr Williamson, who for three years has been a close aide to the Prime Minister, spent Thursday evening and yesterday morning in No10 as Britain went to the polls. Today he paid tribute to Mr Cameron who he described as 'brilliant, honourable, and gifted'.

He also revealed that the Prime Minister always intended to step aside if Britain voted to leave the EU. Mr Williamson said: "Him and I were sat having a cup of tea before phoning the Queen and it was obvious that he felt it was the right thing to do.

"He is a man of immense integrity. He held his belief that Britain was safer and better off in the EU but felt it was not right that given the difference between his beliefs and that of the majority of the country, that he lead the negotiations.

"It was incredibly emotional. I was with him when he and Samantha came back into the office yesterday morning and he said a few words there.

"It is such a fascinating period of my life to work with him and to see how gifted, quick-thinking, and talented he is.

"It is the nature of politics sadly. It is a rollercoaster but I think politicians complaining about the speed of events is like fishermen complaining about the sea.

"He was a Prime Minister who makes big decisions. Over six years as Prime Minister he has done more than most have achieved in 10 years.

"It is deeply sad seeing one of the best Prime Ministers we have had, have to go.

"Having worked with him so closely for three years I knew for a long time that this would be what he would do if this was the result.

"It was incredibly sad. He was a brilliant Prime Minister who has steered the country through difficult times from recovering the economy from the mess left by Labour, to taking action in Syria and Iraq, and calling the Scottish and EU referendums.

"He has not been scared to take a chance and to do what he thought was the right thing for the country.

"He gave the British people an opportunity no other Prime Minister has been willing to do in 40 years and in many people's lifetimes.

On a personal level it has been a privilege to work so closely with him and, of course, it is sad it will come to an end in this way.

"People are very cynical about politicians and think all they care about is clinging to power, but the Prime Minister has shown himself to be a man of decency and what he has done in stepping aside is very honourable.

"He always thought about what would be best for the British people even if that meant setting himself up to relinquish power at Downing Street He did what he thought was the right thing to do even if there were personal consequences.

"I hope history will be kind to him and I believe it will be. Without David Cameron, people would not have had the chance to have their say like they have done. It is now for a future Prime Minister to take us into this new era and make sure it works."