Police have been slammed by a watchdog for using the name of a gun as an alias for an officer involved in a fatal firearms operation.

The pseudonym G36 was chosen as one of a number of aliases used by the Metropolitan Police to hide the identities of armed officers involved in an operation that led to the fatal shooting of an Islington man last year.

The Independent Police Complaints Commission (IPCC) said the decision was “highly inappropriate” as G36 was also a nickname for the standard-issue G36 Heckler-Koch police rifle used to shoot dead Dean Joseph.

The IPCC said: “It is the view of the IPCC investigator that it was highly inappropriate for one of the officers involved in this incident to be given the pseudonym ‘G36’.

“A G36 was the weapon used to fire lethal shots. The weapon is known by officers as a ‘G36’.

“The consequence of this is it adds a layer of confusion into the officers’ accounts as it is not clear whether they were writing about the weapon or the officer.

“Moreover the use of the pseudonym, in the IPCC investigator’s opinion, was insensitive in the circumstances.”

The Met was also criticised for failing to provide the IPCC with the real names of firearms officers involved in the operation for seven weeks after the shooting.

It said timescales should be set for the true identities of armed officers to be revealed so as not to hamper thorough independent IPCC probes into deaths.

Mr Joseph, 40, was shot twice by police marksman Pc Stuart Brown at a flat in Shepperton Road on September 5 last year. An inquest jury last month ruled the killing was lawful.

Unemployed gardener Mr Joseph travelled from a hostel where he was living in Tottenham and broke into the home of his former girlfriend Julie Moyses before taking her hostage at knife-point.

Armed police were called and a local police officer tried to negotiate with Mr Joseph for an hour-and-a-half.

He was shot at 12.51am after moving the knife towards his ex-girlfriend’s throat.

A spokesman for the Met said: “We seek to learn from every operation and we have accepted the recommendations from the IPCC so that we can continue to improve how we deliver armed policing, for the good of the public and our officers.”