Police have arrested a man in his 70s for breaking newly-introduced coronavirus laws, as hundreds of anti-lockdown protesters descended on Trafalgar Square in central London.

Under new changes to regulations, those attending a gathering of more than 30 people may be committing a criminal offence.

Officers from the Metropolitan Police handed out letters explaining the legislation to demonstrators as they marched down Whitehall, and encouraged them to disperse.

But a spokesperson from the Met later confirmed that a 73-year-old man had been arrested at 3.25pm on suspicion of breaking the new Health Protection Regulations 2020.

The spokesperson added that he remains in custody and an investigation is ongoing to identify further individuals who may have breached the new regulations.

A 25-year-old man was also arrested earlier at 1.30pm on suspicion of a public order offence.

He was taken to a south London police station and remains in custody.

Among those present at the “Unite for Freedom” rally were the brother of the former Labour Party leader, Piers Corbyn, 73, and author and broadcaster David Icke, 68.

Prior to the demonstration on Saturday afternoon, in which protesters displayed anti-mask and anti-vaccination placards, the Met “strongly advised” people to avoid large gatherings for their own safety.

“We are still in the middle of a global pandemic,” it said.

“If you attend a gathering of more than 30 people, you may be committing an offence, which is punishable by a fine.

“If you hold a gathering of over 30 people, you might be committing an offence under new changes to the Health Protection Regulations.

“It is your responsibility to check the position and ensure you are not committing an offence by being involved in a large gathering.

“We urge anyone arranging a gathering to inform your local police.

“We all need to continue to do our part to prevent the spread of the virus.”