The head of Britain's police watchdog has said he has serious concerns about the policing of demonstrations after a series of allegations about police violence at the G20 protests this month.
Nick Hardwick, chairman of the Independent Police Complaints Commission, told The Observer newspaper there should be a debate over how police in the UK maintain public order.
'It's got to be a democratic political question about how do we want to be policed,' he said.
'I think that needs a proper parliamentary discussion. The choices we make as a society about that aren't consequence-free. There are tricky balances to be struck.'
The IPCC is investigating three cases of alleged police violence at the protests over the G20 summit in London, including one against a woman and one against a man who later collapsed and died.
The IPCC said on Friday a Metropolitan police officer had been questioned on suspicion of manslaughter over the death of newspaper seller Ian Tomlinson during G20 protests on 1 April.
A police sergeant was suspended last Wednesday after video footage came to light of a female protestor, Nicola Fisher, being hit across the face and beaten by a baton-wielding policeman during protests on 2 April.
Mr Hardwick said the allegations of excessive force by police, and claims that some officers failed to display identification numbers correctly, raised questions about whether police were crossing the line between being public servants or masters.
The IPCC said it had received almost 90 complaints about police behaviour during the protests, which saw confrontations between anti-capitalist demonstrators, environmental campaigners and riot officers.
Some of the allegations stemmed from amateur video footage or mobile phone images of the clashes.
The capital's police chief, Commissioner Paul Stephenson, expressed his concern about the video images and has ordered a review of public order tactics, in particular the use of 'kettling' where officers herd protestors into a confined space and hold them there for long periods of time.
