Arsonists attacking commercial properties with links to people's homes could be shot by police during future riots, an official review of police tactics said.
The use of firearms could be justified given the "immediacy of the risk and the gravity of the consequences", legal advice published in the review said.
Plastic bullets and water cannon could also be used by officers facing riots similar to those seen this summer, the review by Her Majesty's Inspectorate of Constabulary added.
Police need to be better prepared, trained and ready to protect the public if they are to improve their response to similar scenes of violence and looting in the future, the review found. It called for clear rules of engagement to establish "an agreed envelope of available tactics and associated use of force that are likely to maintain public support".
These rules could include making clear that armed police could use firearms with live ammunition during "arson attacks on commercial buildings with linkage to residential dwellings".
The review added that plastic bullets could also be considered when barricades and missiles were used by protesters; during violent attacks on the public in the presence of police; and when other emergency services are threatened. They could also be used when petrol bombs are thrown or during arson attacks.
All of these scenes were experienced by officers this summer.
The review added that water cannon were an "effective means of dispersal and incur fewer injuries to the public" in static and slow-moving scenarios. But it conceded there were none on the mainland UK, they cost more than £1 million each and need to be deployed in twos to be effective.
Water cannon also have to be protected by officers and need access to water as they can empty in "a matter of minutes" if used continuously.
It comes in sharp contrast to a report by the Commons Home Affairs Select Committee on Monday which said it would have been "inappropriate as well as dangerous to have employed water cannon and baton rounds". Their use "could have escalated and inflamed the situation further", the MPs said.
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