London police said Saturday they had arrested dozens of people after thousands turned out in the British capital to protest against ongoing coronavirus lockdown restrictions.

The Metropolitan Police Service said it had made 33 arrests by early evening, most for breaching months-old virus regulations that outlaw leaving home except for a limited number of reasons.

Several thousand people were estimated to have gathered for the demonstrations, which began Saturday lunchtime at Hyde Park.

After the crowd marched through central London, a group of around 100 returned to the park and there were reports of scuffles and of the contingent throwing bottles and cans at officers.  

"Our officers are continuing to engage with people attending the ongoing protests in Central London," the force had said earlier on Twitter. "Those gathering in crowds are being encouraged to disperse and go home. 

"Officers will take enforcement action where necessary. This could be a fixed penalty notice or arrest." England's Covid-19 lockdown measures have been in place since early January when Britain saw a surge in infection rates, hospitalisations and deaths. 

The situation has improved markedly since then, and Prime Minister Boris Johnson last month outlined a gradual easing of the restrictions, with the stringent stay-at-home order set to end later this month.

Anti-lockdown demonstrations numbering hundreds or even several thousand people have occurred regularly during the pandemic, often resulting in a small number of arrests. 

However, the police response to Saturday's protests was under particular scrutiny in light of the outrage over the Met's handling of a vigil last weekend for a woman who was allegedly kidnapped and murdered by a member of the same force.

On that occasion, police scuffled with the predominantly female crowd of several hundred and physically restrained demonstrators, arresting four people. Met Police Commissioner Cressida Dick, who faced calls to resign in the aftermath, agreed to both internal and independent reviews into how officers responded. The episode also sparked renewed debate about legal curbs on protests during the pandemic.

More than 60 lawmakers signed a letter Saturday, co-ordinated by rights groups Liberty and Big Brother Watch, warning that criminalising protest "is not acceptable and is arguably not lawful".