LONDON — Thousands of people protested Saturday in several cities across England and Wales against a sweeping crime and policing bill, with some in London clashing with the police in scenes that may further fuel a raging national debate over law enforcement tactics in Britain.

In London, protesters peacefully marched from Hyde Park in central London to Parliament Square, but the gathering gave way to scuffles with officers in the evening, and 26 demonstrators were detained, the police said. Ten officers also suffered light injuries, the Metropolitan Police said in a statement on Saturday night, adding that the number of arrests would likely increase.

Protesters also marched in Liverpool, Birmingham, Bristol and many other cities on Saturday, the latest events in what have become known as “Kill the Bill” demonstrations. Critics of the bill say it would hinder the right to protest and constitute an attack on democracy.

Among several contentious measures in the Police, Crime, Sentencing and Courts Bill are provisions allowing the police to bar unauthorized encampments and detain protesters if gatherings are deemed a “public nuisance.” The new legislation, pending in Parliament, could also impose noise limits and set start and finish times on demonstrations.

The faceoffs on Saturday come amid an increasingly tense environment between the police and demonstrators across Europe. Over the past year, protesters have clashed with the police during Black Lives Matter protests, anti-lockdown rallies and, in countries like France, against similar security laws.

Human rights groups have warned against rising police disruption of such protests and have cited the arbitrary detention of protesters in countries like France, Croatia and Bulgaria as worrying trends.

“No E.U. country is immune to threats to democracy, and more concrete efforts are badly needed to revert worrying trends,” the Berlin-based Civil Liberties Union for Europe said in a report published last month.

In England and Wales, the new policing bill was thrust into the national spotlight last month after the police broke up a peaceful vigil for Sarah Everard, a 33-year-old woman who was murdered after disappearing in south London on March 3.

Though the vigil was officially canceled because of pandemic restrictions, thousands showed up anyway. Police forces sought to dislodge the protesters, pinning some women on the ground in scenes that shocked the public and drew widespread criticism, including from London’s mayor, Sadiq Khan.

An official inquiry made public this past week determined that the officers had acted appropriately.

“After reviewing a huge body of evidence — rather than a snapshot on social media — we found that there are some things the Met could have done better,” the leader of the inspection team, Matt Parr, said of the Metropolitan Police.

“But we saw nothing to suggest police officers acted in anything but a measured and proportionate way in challenging circumstances.”

The clashes on Saturday may add to the ongoing debate about excessive force used by the country’s police, which in London have been shaken by several recent controversies. Metropolitan Police Commissioner Cressida Dick acknowledged last year that her force was “not free from racism and discrimination,” and Mr. Khan has vowed to make the police more diverse to better represent London’s population.

Unlike the vigil organized last month for Ms. Everard, protests are now legal in England and Wales as long as event organizers make a risk assessment and take measures to limit the spread of the coronavirus.

Several politicians from the Labour Party attended Saturday’s march in central London before it led to confrontations with the police. “We will always defend the right to demonstrate against injustice,” Jeremy Corbyn, the former Labour leader, wrote on Twitter after he spoke at the gathering.

Later in the evening, protesters shouted expletives and clashed with police forces as they tried to disperse them.

Commander Ade Adelekan said in a statement Saturday night that a majority of demonstrators had adhered to social distancing rules and left when asked to by the police. But officers arrested protesters, he added, after a minority refused to comply with orders.

“We remain in the middle of a global pandemic and we have made great progress in controlling the spread of the virus,” Mr. Adelekan said. “We will not allow the selfish actions of a small number of people to put Londoners progress in jeopardy.”