Since British operations in Afghanistan began in 2001, much has changed - not least the kit the soldiers on tour in the country are expected to use.

More than £6bn has been spent on what are known as Urgent Operations Requirements, in addition to the MoD's annual budget of around £34bn.

Staff Sergeant Nick Brown, of the Royal Scots Dragoon Guards, who has done several tours of Afghanistan, explains how the standard issue personal rifle, the SA80, has been modified and updated.

BBC News - UK troops in Afghanistan