Leading article: The police cannot police themselves

Given the CCTV footage showing Ian Tomlinson hit with a baton and then knocked to the ground by Pc Simon Harwood at the G20 protests three years ago, it was never in doubt that the incident took place. The question was whether the riot policeman could be held responsible for the homeless newspaper vendor's subsequent collapse and death. After four days of deliberation, a jury at Southwark Crown Court yesterday concluded not and acquitted Pc Harwood of manslaughter. The matter might be expected to end there. But it absolutely does not.

Only after yesterday's verdict did it emerge that the altercation with Mr Tomlinson was just the latest of a litany of allegations of violence and misconduct spanning much of Pc Harwood's career. Such a history may not have a bearing on the specifics of Mr Tomlinson's case. But it raises questions as to why he was deemed fit to be in uniform to which there are no obvious answers.

Pc Harwood's record includes no fewer than 10 disciplinary complaints in 12 years, including claims of unlawful arrest, abuse of authority and discreditable conduct that could have seen him dismissed, and a string of subsequent allegations of violence and "heavy-handed" policing tactics. Although only one complaint was ever upheld, the details of the alleged offences – and the fact there are so many of them – are nonetheless concerning.

More disturbing still is that Pc Harwood was able to dodge the most serious charges, by all accounts under the nose of his employer. By quitting his force – London's Metropolitan Police – only to rejoin, on the civilian staff, without missing a day's work, Pc Harwood successfully avoided the impending hearing. That his disciplinary record was not probed when he moved to Surrey, to return to uniformed policing, two years later, only adds to the sense of a culture of inexcusable laxity.

Taken together, it is a career that looks alarmingly like another, appalling example of lack of cohesion in the police. Pc Harwood may have been acquitted yesterday. But the police service has more to explain than ever.