The devastating weapon kills people with a massive blast of heat and pressure rather than explosives.
Body armour offers no protection against the weapon.
Its use by the Russians in Chechnya sparked protests from human rights campaigners. BBC Radio 4's Today programme claimed that the weapon was already in development by the Defence Evaluation and Research Agency in Kent and may be in service by 2005. However, a statement given to the programme by the Ministry of Defence suggested that Britain's plans may be less well-advanced. It is possible that this might involve a thermobaric solution. We would, of course, ensure that this is fully in accordance with international law.