Police handling of the Climate Camp in Kent was criticised
Police are too heavy-handed in dealing with protests, harassing and intimidating people, a leading parliamentary committee has said.
The Joint Select Committee on Human Rights also criticised the misuse of legislation used against demonstrators.
It says peaceful protesters have had personal property seized and have been intimidated by police.
It wants tighter restrictions to prevent the use of anti-terrorism laws. Police say they are acting lawfully.
The committee also said police were too heavy-handed with journalists reporting on demonstrations. It comes as police forces prepare to deal with large-scale protests in London ahead of the G20 summit.
In a statement, the committee said police had used "legal powers not designed to deal with protests such as anti-social behaviour legislation and the Protection from Harassment Act 1997".
It added: "Witnesses also referred to local authority restrictions deterring protest, such as requiring third party insurance or licences for the use of sound equipment."
It also found the use of officers in riot gear to police protests could "unnecessarily raise the temperature" of crowds, making conflict more likely, and said police should not be using Taser stun guns at peaceful protests.
'Striking a balance'
Protesters at the Climate Camp in Kent last year - a demonstration against the building of a new power station - accused officers policing the protest of seizing tent pegs and a clown costume.
At one point 1,500 officers, including riot police, were dealing with only 1,000 protesters, organisers said.
Kent Police have asked the police watchdog to investigate their policing of the camp.
Committee chairman Andrew Dismore said: "The right to protest is a fundamental democratic right and one that the state and police have a duty to protect and facilitate.
"Of course there is a balance to be struck between the rights of protesters, the police and the public, but the state must not impose restrictions unless it is necessary, and proportionate, to do so.
"That is a high threshold. The presumption is in favour of protest without state interference. We believe there are changes to the law and practice that are needed to make that presumption a reality."
The report has also accused police of heavy-handedness against journalists.
It said the National Union of Journalists had claimed police indulged in "intrusive" filming, denying them access to protests, refusing to recognise press cards and even assaulting them.
It said it was "unacceptable that individual journalists are left with no option but to take court action against officers who unlawfully interfere with their work".
A Metropolitan Police statement said: "Human rights and the right to protest are at the heart of our policing philosophy.
'Communication is key'
"The report recommends what is already routine practice in relation to the policing of protests in London. The MPS has a long history of successfully policing marches and demonstrations. Thousands of these type of events pass off without incident every year in the capital.
"However, the MPS also has a duty to ensure that the rights of others are protected. We will always facilitate lawful protest and are committed to doing so but do have to minimise the disruption caused to others going about their lawful business."
The Association of Chief Police Officers (Acpo) said "communication is key".
"We seek to strike a balance between the lawful rights of protesters, and those of people to go about their daily life unimpeded.
"Where there is open dialogue with protest organisers we are able to ensure that policing of protests is proportionate and necessary, rather than going in heavy-handed or allowing situations to build up to a flashpoint before intervening.
"There are always a small minority of protests, or fringe groups within protests, which will cause problems. Where mistakes are made we must learn from them."