Joe Carlebach is a Councillor for Avonmore and Brook Green Ward on Hammersmith and Fulham Council.

Many Londoners were bemused by Theresa May’s decision to deny Boris and the Met the use of water cannons in London. They understand that this part of the policing arsenal would only be used in exceptional circumstances. It would not be a feature of life in the capital.

There are two main aspects to why Boris was right to ask, and why the Home Secretary was wrong to say no. First, deploying water cannons would only be sanctioned in extraordinary circumstances, with the aim of protecting Londoners, their homes and their businesses – surely this is better than using “lethal” force such as firearms. It is also a deterrent for those intent on mass violence and anti-social behaviour, and, as we know from history, deterrent has a real value in maintaining good order. Adequate sign-off safeguards could easily be put in place to ensure that the deployment of water cannons was very much the exception rather than the rule.

Any reasonable measure that helps with the maintenance of law and order, and especially with the protection of ordinary people, must be a priority. As is always the case, it is not the political elite or the wealthy who suffer most when law and order begins to deteriorate. It is ordinary citizens, the vulnerable (especially the elderly), and the small business owners whose premises are looted and destroyed.

The second reason why this was an erroneous decision is the clear gap in standards between London and Northern Ireland. Many of us fail to understand why the use of water cannon is “appropriate” in Northern Ireland but not in London. Either this measure is an acceptable tool for law and order, or it is not. The good people of Northern Ireland are quintessentially no different from the good people of London. We are all citizens of the United Kingdom, and we should all have the same rights under law.

There is, and has been for many, many years, a vibrant Northern Irish community living in and contributing to London. It is simply irrational that members of this community (and any of us visiting the province for that matter) can be protected by the use of Water Cannon when in Northern Ireland, but not when they return to London.

I believe many Londoners feel let down by this misplaced decision. I say again, to be absolutely clear, that I do not want to see the regular use of this equipment. But many would feel safer in our much-loved city knowing that there was another non-lethal option to uphold the peace and to support the all-too-stretched “thin blue line” in exceptional circumstances.

The Home Secretary (for whom I have a huge amount of respect) might do better to concentrate her efforts on resolving the burgeoning crisis in and around Calais. Amazingly, this seems to have caught the authorities by surprise and is having such a huge impact on our hauliers, holiday makers and the citizens of Kent. Her time would be better spent solving that problem, rather than thwarting the legitimate moves of a democratically elected Mayor acting to protect his citizens.