Met holding water cannon talks
The Government is in talks with Scotland Yard about introducing water cannons to the force's arsenal.
The Metropolitan Police wants to use two German-made water cannon vehicles, each capable of holding 9,000 litres of water, according to a report in The Times newspaper.
The Home Office, which must approve the use of any police weapon, confirmed it was in discussions with the Met over the use of the controversial equipment.
A Home Office spokesman said: "We will ensure forces have the tools and powers they need to maintain order on our streets. We are currently providing advice to Acpo (Association of Chief Police Officers) and the Metropolitan Police as they build the case for the use of water cannon."
After the 2011 riots, the Met stepped up riot training and increased the availability of plastic bullet guns.
The force believes water cannons would be a "valuable" addition to their armoury when faced with similar situations in the future.
It is understood that the Met had hoped to have the vehicles by next month in case disorder arises from protests planned for London before the G8 summit in Northern Ireland.
The Police Service of Northern Ireland (PSNI) has six water cannon vehicles, which are sent out in pairs and have been used to tackle disorder arising from sectarian clashes among other situations.
It was reported that the Met wants to use the Ziegler Wasserwerfer 9000, which cost £1.3 million each.
London Assembly Labour group police and crime spokeswoman Joanne McCartney AM said: "The evidence for the effectiveness of water cannons is very unclear. Against the widespread rioting we saw in London water cannons would have been of very limited, if any, use. We clearly need more police officers and we need them to be riot-trained. Water cannons are no replacement for a properly resourced and functioning police service."