The gun buy back programmes were sponsored by local law enforcement officials who offered people pre-paid debit cards for working guns, no questions asked.

Those who handed over working guns at community churches and other turn-in sites in the two cities were given JPMorgan pre-paid debit cards which can be used at ATMs and the point of sale.

Police in Chicago have collected more than 6800 firearms during the city's "Don't Kill a Dream, Save a Life" gun turn-in programme. People who turned in firearms were given $100 JPMorgan pre-paid debit cards for weapons and $10 cards for ball bearing guns, air rifles and replica guns.

A separate programme sponsored by the New York Police Department and the Brooklyn district attorney's office netted almost 700 guns. People who dropped off guns received a $200 pre-paid debit card, whilst ball bearing guns and air pistols were exchanged for $20 cards.

In Brooklyn 204 revolvers, 193 pistols, 226 rifles and shotguns and 12 assault weapons were collected, which will be melted down into clothes hangers and used at dry cleaners.

Explaining the use of pre-paid cards for the programmes, Laurie Neill, MD, public sector solutions, JP Morgan, says: "Programme administrators are able to distribute cards on the spot at collection locations and do not have to worry about the additional time, costs and oversight associated with paper cheque distribution. Participants are paid instantly and have immediate access to their funds instead of having to wait for a cheque to arrive in the mail or taking time to cash a cheque."

The Brooklyn and Chicago programmes follow a similar move in Buffalo in June last year which saw more than 800 weapons collected in eight hours in exchange for over $42,000 in pre-paid debit cards.