One of Britain's most prominent human rights lawyers has likened "heavy-handed" and politicised treatment of student protesters to the brutal victimisation of the miners during the strikes of the Thatcher era.

Michael Mansfield QC said "outrageous" tactics were being employed to quash political protest and peaceful demonstrations in the UK, within politics, the police and the judiciary.

Known for taking on some of the highest-profile cases of recent years – including the Stephen Lawrence murder trial, the Guildford Four case and the defence of Barry George, who was convicted of the murder of Jill Dando but then acquitted at a retrial – Mansfield revealed that he is to leave partial retirement to act on behalf of Alfie Meadows, a 20-year-old student who suffered head injuries during a tuition fees protest last December.

Meadows, who was left with brain damage after being allegedly struck on the head with a police officer's baton, is awaiting trial on charges of violent disorder. Mansfield said the right to protest in Britain was under serious threat and that people who wanted to go on peaceful demonstrations now had to weigh up the risks they faced from heavy policing and draconian sentencing.

"We praise those in the Arab spring and condemn the force used against them by their governments, yet allow our own rights to be eroded," he said. "What is happening here? A direct attack is being made on the right of people to go out on the streets and show their solidarity and unity with others of the same opinion and hold peaceful protest."

His warning came amid controversy at unusually harsh prison sentences handed down to students Charlie Gilmour, 21, and Francis Fernie, 20. Fernie was jailed for a year for throwing two sticks at police lines at TUC anti-cuts protests. Gilmour was sentenced to 16 months for "outrageous and deeply offensive behaviour". He had thrown a bin at a Rolls-Royce carrying Prince Charles, kicked at shop windows and swung off a war memorial. Both claimed to have "got carried away in the heat of the moment" and offered profuse apologies.

Gilmour's mother, Polly Samson, who is married to Pink Floyd guitarist Dave Gilmour, called her son's sentence a waste of taxpayers' money. An appeal is to be heard this week. She believes students were paying a "very heavy" price under a "catch-all" charge of violent disorder. Cambridge University has not confirmed whether Gilmour will be allowed to continue his studies after serving his sentence.

Mansfield and other leading legal figures believe Gilmour and Fernie were made scapegoats to show disapproval of public objections to government policy at a time when the process of democracy was weakened by the disempowering of politicians by the expenses scandal.

"There is a direct comparison to what was going on during the miners' strike," said Mansfield, "a shameful tradition … of riot squads or tactical support groups or response units, whatever you want to call them. They go in hard and heavy, and the whole idea is to intimidate, not those who are not intending to commit crime, but those who are presenting opposition to the government."

He attacked the brutality that can come from a "unit mentality". "When there is a culture of a unit, they share a uniform, they share an ethos, things can get out of control and that is something that has run from Blair Peach through to Ian Tomlinson [the newspaper vendor who died after being attacked by a police officer] and I fear the police still haven't got their heads round this at all.

"They have to be reminded that there is a right to peaceful protest in Britain and it worries me how many cases that shouldn't ever have left the ground are ending up in the courts when there may have been an inconvenience to the public, a trespass, but nothing criminal."

He said it was a low-level politicisation. "I don't think it's done at cabinet level, but there is a very strong consciousness in the echelons of power of making examples of people."

Mansfield, who has been asked to stand for the chancellorship of Cambridge University, says that a 1966 UN agreement commits states to aim to provide free further education, so tuition fee protesters were on the side of the law.

Many lawyers are concerned at the age of those facing court for little more than getting over-excited or scared by police kettling techniques and horse charges. Some 200 officers have been assigned to finding those who took part in the UK Uncut sit-ins and the tuition fees protests.

Raj Chada, a lawyer with Hodge Jones & Allen who represented Jonathan May-Bowles, the man jailed for throwing shaving foam at Rupert Murdoch, said he had real concerns that a person now arrested during a political protest could expect harsher treatment than someone who committed a similar offence when not at a protest: "The fact they are at a political protest is now being treated as an aggravating factor, rather than a mitigating factor."

The tough approach by police and judges was having its desired effect, he said. "When I have spoken to protesters, some on the fringes say they do not want to go on protests any more. There are real concerns that the judiciary is being unduly harsh on political protesters."

The judge who presided over the Gilmour and Fernie cases refused their appeals for community service orders.