The Sunday Times - A police chief has warned for the first time that forces will fail to meet the government’s pledge to increase the number of armed officers, made last year to reassure the public about the country’s ability to combat a severe terrorist threat.

Speaking after last week’s attack on Westminster, Simon Chesterman, the lead expert on armed policing for the National Police Chiefs’ Council, said they faced a “massive challenge” in recruiting the extra 1,500 firearms officers that were promised — and warned that forces would not be able to deliver on the pledge made by David Cameron last April. The number of armed officers has fallen from 6,976 in 2010 to 5,639 last year

Chesterman said problems in attracting recruits had been created by the Independent Police Complaints Commission’s (IPCC) insistence on treating armed officers as suspects each time they discharge weapons. His warning comes as it emerged that security at the gates breached by the Westminster attacker Khalid Masood had been downgraded two months ago. Armed officers were removed and replaced by unarmed police, one of whom, PC Keith Palmer, was killed by Masood.

The Sunday Times understands that senior Met chiefs changed the rota at the carriage gates from a “static” patrol, involving a permanent deployment of two armed officers, to unarmed sentries supported by an occasional “roving” group of armed officers who check the location every hour.

It is understood the decision was taken to cover a shortfall in the number of armed police officers available to guard key landmarks in London.

The change was made despite a recent “table-top” exercise conducted by the police and the Commons authorities to test parliament’s defences, which ended up with four “terrorists” managing to storm the House of Commons and kill dozens of MPs.

Yesterday former Met commissioner Lord Blair said he was “absolutely certain” there would have to be changes to security at the entrance gates.

Chesterman said: “The uplift [in the number of armed officers] has to be delivered by March 2018, and there are concerns about the numbers. I don’t think we are going to achieve them. It is a massive challenge. The training is running very, very hot at the moment. It’s like trying to fill up a bath with the plug out.”

Nationally, the number of armed officers has fallen from 6,976 in 2010 to 5,639 last year.

Cameron announced a review in 2015, after being briefed at the national security council that the fight against terrorism was being compromised by the police watchdog.

However, Chesterman said potential recruits had been put off by IPCC guidance that states officers should be separated following a shooting to prevent conferring.

“They are often traumatised by their experiences, where they have either taken a life or been put in life-threatening situations themselves, and the current guidance would make them feel like they are under arrest.”

Chesterman expressed “frustration” that the review of the law announced by Cameron had not been completed.

“Firearms officers were comforted and reassured by the announcement, but on the ground they have seen very little progress. It is a significant concern, and it’s unsettling recruitment and retention.”

The IPCC denied treating officers as suspects and said their new guidance would “help the public have confidence that police actions are independently scrutinised”.