Most of the new officers will be trained within the next two years after the Prime Minister, David Cameron, set aside £143m to boost the country's armed response capability.

But is it enough to meet the challenges they face?

The number of firearms officers fell from nearly seven thousand in 2009/10 to under six thousand in 2013/14.

And, despite the extra funding, the Police Federation is concerned the new firearms teams will have to come from existing staff. They say that will deplete the number of officers available for other duties.

BBC Home Affairs Correspondent Danny Shaw investigates - and he examines growing unease at the way in which those who discharge their weapons are dealt with.

Concern has been highlighted by the suspension and arrest of the officer suspected of shooting dead Jermaine Baker in Wood Green in December.

Police representatives tell the programme that while they expect their actions to be investigated, people will not come forward to train as firearms officers if they believe they will be treated like a criminal who fires an illegal weapon.

The Independent Police Complaints Commission acknowledges that firearms officers work in challenging circumstances but maintains that police shootings resulting in death or serious injury should be independently investigated.

So, can the system for holding them to account be improved?

Reporter: Danny Shaw Producer: Ian Muir-Cochrane.