The Independent Police Complaints Commission (IPCC) has emphasised the key role photographs play in its investigations into alleged police wrongdoing.

IPCC Commissioner Deborah Glass told Amateur Photographer: ‘Photos can play a vital role in any investigation. They help inform investigators about events surrounding the incident, identify key witnesses and can help determine lines of enquiry.’

The statement comes as the emergence of new G20 protest images highlight the power of the ‘citizen journalist’ in helping to resolve cases investigated by the IPCC.

Video images showing police treatment of Ian Tomlinson – who later died of a suspected heart attack – were captured by a member of the public.

Yesterday, more amateur footage emerged, apparently showing an officer attacking a female protester. It had been posted on the video sharing website YouTube.