The claim

“The way we police in Britain is not through use of water cannon. The way we police in Britain is through consent of communities.”
Theresa May, 9 August 2011

The background

Days of mob violence across London and beyond have led some commentators to question whether the police should be cracking down harder on rioters.

Shadow Public Health Minister Diane Abbott called for a London-wide curfew, while Tory MP Patrick Mercer suggested that the use of plastic bullets and water cannons should be imported from Northern Ireland to the British mainland.

The Home Secretary, Theresa May, has ruled out calling in the Army, but Scotland Yard Deputy Assistant Commissioner Stephen Kavanagh appeared to contradict that when he said that nothing had been ruled out.

Which of these measures are available to the police and what are the chances of them being put in place?

The analysis

Mrs May hinted last year in the wake of the student protests in central London that she was considering the use of water cannon to disperse crowds, before apparently changing her mind.

She appeared to rule out the use of high-pressure hoses in response to the latest disturbances in an interview on Tuesday when she said: “The way we police in Britain is not through use of water cannon.”

But it’s far from clear that the Home Secretary has the authority to restrict the use of controversial tactics like water cannon.

The Association of Chief Police Officers (ACPO) told FactCheck that its guidance to chief officers on the tools available to them for crowd control included water cannon, plastic bullets, “screening smoke” and CS gas.

The position is that an officer of the rank of Assistant Chief Constable or Commander is at liberty to authorise any of these tactics if he deems the circumstances are serious enough without the need for consent from the Home Secretary or a change in legislation first.

That’s not to say that we’re suddenly likely to see any of those weapons called into play in the coming days, for practical as well as political reasons.

None of them have ever been used before on the mainland, so there will be very few officers available who are trained in their use, and a lack of equipment on the ground.

It’s understood that water cannon would have to be shipped over from Northern Ireland if Met chiefs wanted to use them.

Mr Kavanagh has signalled that plastic bullets, also commonly used in Northern Ireland, remain a possibility, saying: “Through the night the Commissioner did absolutely consider that as one of the tactics available to use,  a tactic used if deemed necessary.”

He hinted that the special ammunition is currently available but added that the use of baton rounds may not be effective against the rioters, saying: “These are very fast-moving mobs – by the time we get baton guns there, they will have moved on.”

The size and speed of the mobs has also made the Met’s favoured crowd control technique of containment or “kettling” difficult to implement.

As well as practical considerations, Mr Kavanagh has also indicated that senior officers have serious reservations about using heavy-handed tactics, saying he was “not going to throw 180 years of policing with the community away”.

An awareness of policing history also makes it unlikely that armed police will be deployed to control crowds, although ACPO guidelines do make that option available for senior officers even if rioters are not armed themselves. The guidance says marksmen can be sent out to protect the public and other officers from anyone who is “so dangerous that the deployment of armed officers is considered as appropriate”.

There have also been calls for a curfew, but ACPO told us there is no instrument in British law to put such a measure in place.

The 2003 Anti-Social Behaviour Act allows police to escort home under-16s found in certain designated zones.

But the law doesn’t apply to adults and does not even give police the power of arrest over children. No legislation that would enable the Met Police to declare a general curfew appears to exist.

FactCheck can also find no legal barrier to the deployment of the Armed Forces on the streets of mainland Britain, although there is likely to be overwhelming political opposition to such a move.

The verdict

Despite the political debate over the use of water cannons, it appears to be the case that they are already a live option, along with CS gas, screening smoke and plastic bullets, and it will be up to the police rather than ministers to sanction their use.

So Theresa May might not approve of hosing down rioters, but it’s not technically her decision. Whether a career policeman would want to risk the wrath of the Home Secretary by going against her express wishes is, of course, a very different question.

Putting soldiers on the streets and the more widespread use of armed officers also remain theoretical, if even less likely, possibilities.

There would be serious practical and political objections to the use of any of these approaches, but the Met has shown this week that is prepared to adopt tough new tactics.

Officers have been using armoured vehicles called Jankels for the first time, driving them at speed towards groups of looters, in a sign that crowd control measures are always evolving.

By Patrick Worrall