The number of police firearms officers plunged by nearly a fifth in five years, new figures have revealed - sparking fresh questions about the capacity to respond to a terrorist attack.
There were 5,647 authorised firearms officers (AFOs) in forces across England and Wales as of March 31 last year, Home Office data shows.
It means the number fell by more than 1,300, or 19%, compared with five years earlier, while it was also down by 217, or 4%, on the previous year.
It is also the lowest level since 2009, the earliest year for which the data is directly comparable.
The disclosure comes at a time when the police service's firearms resources are under close scrutiny in the wake of terrorist atrocities in Europe.
Earlier this month Prime Minister David Cameron announced that more armed officers are to be stationed across the country to deal with a Paris-style attack.
Forces are training around 1,500 extra personnel as part of counter-terrorism efforts, with 400 ready to be deployed to cities outside London around the clock.
However, rank-and-file leaders have questioned where the additional strength will be drawn from, while there have also been calls for a review into the legal protection for armed officers.
Shadow police minister Jack Dromey said: "Police leaders have said time and time again that without sufficient firearms capability, we would struggle to cope in the event of a terrorist attack.
"The Tories need to put the safety and security of our country first, properly funding the police service and the vital role of firearms officers."
Che Donald, of the Police Federation of England and Wales, said: "The figures show that since 2009, there has been an 18% decrease in the number of AFOs.
"So, while the Home Office has pledged to increase the number of AFOs by 1,500, having lost 1,259, in real terms we are looking at an uplift of approximately 250 firearms officers."
Simon Chesterman, the National Police Chiefs' Council lead for armed policing, said the fall in the number of AFOs reflects a move to "more collaborative arrangements", with armed officers working regionally rather than in individual forces.
"Decisions on numbers were based on local threat and risk assessments," he said. " The arrangements have maintained an effective armed policing capability to protect the public in all areas of the country, as well as enabling forces to make efficiency savings in response to budget cuts."
He added: "Following the terrorist attacks in Paris and Brussels, we closely examined our ability to respond to a similar attack in the UK and determined that we needed to recruit and train more armed officers to meet the escalation of the terrorist threat.
"Several forces have recently announced plans to increase their number of AFOs and the Government has provided additional funding. Together this national and local funding will deliver an extra 1,500 officers over the next 18 months."
He admitted recruitment to the roles "will be a challenge", saying: " New AFOs will be existing police officers who volunteer for a highly responsible and dangerous job to protect the public.
"These officers will want reassurance that in the rare event that they discharge their weapons they will be treated as highly trained professionals who were carrying out their duty on behalf of the state, with the intention of protecting the communities they serve."
The Home Office pointed to the announcement that £143 million will be provided to step up the armed policing capability and capacity to respond to a firearms attack.
Policing Minister Mike Penning said: "The use of firearms by the police should always be a last resort, considered only where there is a serious risk to public or police safety."
There were a total of 14,666 police firearms operations in the year ending March 2015 - a decrease of 2% (273) compared with the previous year.
There were six incidents in which the police discharged firearms, up from two in the previous year.
Separate data showed there were 10,329 uses of Taser by police - a 2% increase on the previous year, but the proportion of discharges decreased by one percentage point to 19%.