Arsonists attacking commercial properties with links to people's homes could be shot by police during future riots, an official review of police tactics has 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 (HMIC) 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.
They are a "good option to protect vulnerable areas and premises", but it conceded there were none on mainland UK, 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 yesterday 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.
The report said that while current guidance already allowed the use of force, commanders were prevented from using some of the more forceful tactics due to a lack of training and resources.
Some forces ran out of shields, not all forces train to use plastic bullets in public order situations, and protective equipment was not always available.
Police also need to outnumber rioters by between three and five to one if they are to effectively move forward, make arrests and disperse groups, the review said.
It found that police training, tactics, equipment and organisation was developed largely to deal with set-piece single- site confrontations, and were not prepared for the widespread, fast-moving and opportunistic criminal attacks seen in August.
But the review also said it would be difficult to justify bringing in soldiers to help tackle riots on the streets.
"It is difficult at present to conceive of a purely public order situation in which the level of force for which the military are currently trained in and equipped to use would be justified," the report said.
But the military could be used "to take over logistical roles to free police officers for public order duties".
The HMIC review also called for a "central information 'all source' hub", drawing together all information, including that from direct contact with the public and social networking sites, to be developed.
Policing Minister Nick Herbert said the report was simply stating the existing law in relation to the use of lethal force by the police.
"It has always been the case, and should remain the case, that the police can act - including when absolutely necessary, either in self defence or in the defence of others, against the threat of death or serious injury - with the use of lethal force," he told the Commons Home Affairs Committee.
"To draw from that the suggestion that Sir Denis in his report has recommended this today would go too far. This is simply a statement of the existing law."
Shami Chakrabarti, director of human rights campaign group Liberty, said: "The police have always been able to use violent force to save lives in extreme situations. No new power or strategy is required for that to remain the case.
"But how on earth would bullets have quelled and not inflamed this summer's riots? Didn't the widespread disorder all begin in Tottenham with a fatal police shooting?"