Health Secretary Matt Hancock has SLOTXO admitted breaching social distancing guidance, saying: "I have let people down and am very sorry."
His apology followed photos published by the Sun newspaper showing him in an embrace with a colleague, Gina Coladangelo.
The paper says the photos of the pair - both of whom are married - were taken inside the Department of Health and Social Care (DHSC) on 6 May 2021.
Labour and the Liberal Democrats have said the health secretary should be sacked.
What is the social distancing guidance?
Social distancing in workplaces is not a legal requirement, but is recommended.
The Health and Safety Executive (HSE) says: "Where possible you should keep people 2m apart. If this is not viable, keeping 1m apart with risk mitigation is acceptable."
The government's guidelines say: "When you cannot redesign an activity to meet social distance guidelines, ask if your business can continue without that activity."
What did law say about meeting indoors?
On 6 May, England was still at Stage 2 of Covid restrictions.
When it came to gatherings indoors, the law stated: "No person may participate in a gathering... which consists of two or more people and takes places indoors."
There was an exception for work purposes but only if the gathering was "reasonably necessary".