The Health Secretary resigned after he breached social distancing guidance by kissing a colleague.
In a letter to the Prime Minister he said the government "owe it to people who have sacrificed so much in this pandemic to be honest when we have let them down".
The resignation comes after pictures emerged of Mr Hancock with Gina Coladangelo, reportedly taken on 6 May this year.
He had been under increasing pressure to quit, after The Sun published pictures of Ms Coladangelo and Matt Hancock who are both married, kissing.
The newspaper said they had been taken inside the Department of Health a government building.
In a video posted on Twitter earlier today, Matt Hancock said: "I have been to see the prime minister to resign as secretary of state for health and social care."...
— Matt Hancock (@MattHancock) June 26, 2021
Boris Johnson said he was "sorry" to receive the resignation.
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