Police wanted to fire plastic bullets at rioters in south London last summer but were unable to do so because specialist units had been deployed elsewhere in the capital, according to an official report into policing of the August disturbances.

The Metropolitan police's response to the riots reveals the force has increased its capacity since the riots "to make more agile use" of the weapons.

Baton rounds, intended as a less lethal alternative to regular firearms, have never before been used on the UK mainland. Concerns were raised when the Met said the weapons were on standby during the riots, which began in Tottenham, north London, on 6 August and spread to towns and cities across England.

More than 4,000 people have been arrested since the riots and the Met report describes the investigation, arrest and prosecution of suspects as an "overriding success".

On Tuesday a teenager who killed Richard Mannington Bowes, 69, who had been trying to put out a fire in a dustbin near his home in Ealing, west London, was named as Darrell Desuze after an order banning his identification was lifted.

In 2010, Desuze, 17, attended a school trip to the Met's riot training centre in Gravesend, Kent, where he watched a simulated riot with officers pelted with bricks.

Desuze's experience on the school trip was singled out in Isleworth and Syon school's annual review, which reported how he and his classmates "were treated to the sight of police officers in full riot gear with protective shields engaged in a petrol-bombing situation".

The school report added: "Darrell Desuze, for one, found out that a career in the Metropolitan police certainly would be a lot more interesting than he originally imagined."

The Met's strategic review into its handling of the riots reveals that commanders twice considered using baton rounds, also referred to as attenuated energy projectiles.

On the second night of riots, when trouble broke out in Enfield and Brixton, senior officers decided against using plastic bullets, fearing that doing so could "raise the level of retaliation of the crowd thus increasing the likelihood of individuals, with the capacity to do so, arming themselves with firearms", the report says.

The following night saw unprecedented disorder across London. It included Desuze's fatal attack on Bowes, which Mr Justice Saunders, sitting at Inner London crown court, said was the most serious crime committed during the riots in terms of its consequences.

The most intense disorder was in Croydon, south London, where Met commanders again considered using baton rounds. On this occasion two "kestrel" units – specialist firearms officers who use plastic bullets – had been stationed in Tottenham and Clapham Junction.

"It did not prove possible to mobilise the resource quickly enough to the south to deploy at a time where its use would have been proportionate," the report says.

At the time of the riots, Sir Hugh Orde, president of Association of Chief Police Officers (Acpo), cautioned against deploying baton rounds. "I do not think it would be sensible in any way shape or form to deploy water cannon or baton rounds in London," said Orde, who deployed plastic bullets during his time as the chief constable of the Police Service of Northern Ireland.

"Baton rounds are very serious bits of equipment. I would only deploy them in life-threatening situations. What is happening in London is not an insurgency that is going to topple the country. There are eight million people in London and it is a tiny proportion doing this. They are gangs of looters and criminals and although it is concerning it has to be kept in proportion."

The report, Four Days in August, says the Met is "undertaking work on the use of more assertive tactics in a public order context", but recognises the need for a wider debate on what is acceptable to the public.

Recently, the force has begun deploying plainclothes officers to work as arrest teams at protests, a tactic it has deemed a success. The Home Office is considering whether to purchase three water cannon vehicles.

The report says failings in the Met's community engagement meant it was slow to spot tensions over the death of Mark Duggan, whose fatal shooting by police was the initial trigger of disorder in Tottenham. It proposes a drive to reach out to communities in the capital, particularly people under the age of 30. It also says the force is reviewing its stop-and-search strategy and "frontline" engagement with young people.

Assistant commissioner Mark Rowley, who conducted the Met's review, said: "What I hope isn't lost amongst the public's reading of our detailed analysis is the extreme situation and the individual acts of heroism that took place across London.

"The summer was without precedent and as a result stretched the [Met] beyond all anticipated capability. However I accept this will be of little comfort for those who were victim to the violence, looting and arson."