The head of the Metropolitan Police has reacted cautiously to the prospect of acquiring water cannon to deal with any future outbreaks of rioting.
Bernard Hogan-Howe acknowledged that police needed to review their tactics in the light of last summer's disturbances.
However he said water cannon had limitations and were "not the answer" to the problems which confronted police last August.
After a review of police tactics by HM Chief Inspector of Constabulary Sir Denis O'Connor controversially suggested officers could shoot arsonists if they posed a threat to life, Mr Hogan-Howe said he did not believe arming riot police was an option.
"I don't see foreseeably at the moment that is an option," he told the BBC Radio 4 Today programme.
Mr Hogan-Howe said police needed to have an open mind about all possibilities when it came to dealing with future disturbances.
"We can't see that sort of thing happen and stand idly by and say we will just stand by our old tactics. I think that we do have to have an open mind," he said.
However, while water cannon were effective in some circumstances, he said that there was a limit to their usefulness.
"We have seen them in Northern Ireland, they have been effective there, but they do have their limitations," he said.
"There is certainly an argument for them. In any country, if you haven't used things before then, of course, nobody is going to go willingly towards this new approach. I am not a passionate zealot for this.
"Of course these things are expensive, most of the time they just sit there doing nothing, and they are not the answer."
Mr Hogan-Howe said the focus now of the Met was to try to prevent disturbances starting in the first place and, if trouble did break out, to ensure they had sufficient police numbers to deal with it.
"The principal thing that we have looked at is to make sure that we have the right resources available and that we are able to mobilise them," he said.
"There weren't enough officers available on that Saturday night in Tottenham so we need enough officers, they need to be well-equipped, well-trained, and available to deal with what was a very difficult situation."