A number of questions are surrounding the circumstances which led to an officer being shot at a police station, a former superintendent has said.

Ex-Metropolitan Police officer Leroy Logan said there was a lot of pain caused by the incident and there could be “a lot of learning”.

He told BBC News: “The first thing you want to know is how did this happen?

“How did that person come to be in the station whether it’s in the yard or the building itself and be able to produce a weapon, whether it’s on them at the time.

“It depends on the calibre of the weapon, because, obviously, if it’s a small weapon and it can be easily in that person’s clothing then obviously it brings another question on how thoroughly that person was searched, if at all.

“Those are the things the department for professional standards will look at and the Independent Office for Police Conduct as well as the investigating officers who will have to look at this thing thoroughly.

“Because there’s a lot of learning and obviously there’s a lot of pain for the family and friends and colleagues of that officer who has fallen in the line of duty.”

Mr Logan said the procedure followed will depend on the circumstances in which police come into contact with a suspect.

He added: “It depends if that person was arrested outside the police station and has been transported in a vehicle.

“Invariably these officers will search that individual to make sure they haven’t got anything that can harm other people or themselves.

“Or try and hide any material whether it’s drugs or any sort of articles that they shouldn’t have.

“That’s standard procedure and of course that’s for security reasons just in case they have got a weapon.

“There are circumstances where someone might turn up at the custody suite area itself in the reception and are led straight through.

“So not knowing all of the details, how this person got into the secure area of the station, whether it’s outside the building or in the yard or whatever, we just need to try and find out what’s happened because the details are very, very scant.”

Meanwhile Dal Babu, a former Metropolitan Police chief superintendent, set out the typical procedure officers would carry out when someone is in custody.

He told LBC: “The search should have taken place outside, you would expect that to take place at the time of the arrest.

“Then once they’re inside the police station you would perhaps do a more thorough search, the custody officer may authorise a strip search.

“And that’s when you may find other weapons on individuals.

“But officers are required, for officer safety purposes, to carry out the search at the time of the arrest.”

He said the number of custody suites across London has reduced and officers are having to travel long distances to take prisoners to particular custody suites and need to call up in advance to find out where there is space.