British Prime Minister Boris Johnson has apologized after being fined for breaking his own COVID-19 lockdown laws. 

His wife Carrie and his finance minister Rishi Sunak also received fines for breaching restrictions on social gatherings during events at the Downing Street property where the prime minister lives and works.

Police have been investigating 12 gatherings at Downing Street and the Cabinet Office after an internal inquiry found Johnson's staff had enjoyed alcohol-fueled parties, with the British leader attending a few of the events himself.

Johnson was fined for attending an event to celebrate his birthday on 19th June 2020, his office said. Johnson previously said he had been unaware that the gathering had been arranged.

He said he accepted that people had the right to expect better from their leader and offered a "full apology."

"At that time it did not occur to me that this might have been a breach of the rules. But of course the police have found otherwise and I fully respect the outcome of their investigation," he added.

The police said they would issue more than 50 fixed penalty notices, or fines of around $260, to those who attended gatherings in Johnson's offices and residence in breach of lockdown rules.

Opponents have urged the prime minister to resign over the issue. "Boris Johnson and Rishi Sunak have broken the law and repeatedly lied to the British public. They must both resign," Labour Party leader Keir Starmer said in a statement. "The Conservatives are totally unfit to govern. Britain deserves better."