The Defence Export Service Organisation (DESO) is a UK government department within the Ministry of Defence which promotes arms exports by arms companies based in Britain.
The DESO has traditionally been headed by executives of defence companies who are officially seconded from their employer and continue to receive their salary. A third of the DESO's 500 staff are involved in support of the Al Yamamah contracts with Saudi Arabia. DESO is involved in the Defence Systems & Equipment International exhibition.
Gordon Brown announced on 26 July 2007 that DESO would be transferred to UK Trade & Investment from April 2008, and will be called the UKTI Defence and Security Group. Nevertheless, the Al Yamamah contracts will stay within the remit of the Ministry of Defence
The organisation was founded in 1966 by Denis Healey, the Secretary of State for Defence at the time. In January of that year he informed Parliament that "while the Government attach[es] the highest importance to making progress in the field of arms control and disarmament, we must also take what practical steps we can to ensure that this country does not fail to secure its rightful share of this valuable commercial market." From being called the Defence Sales Organisation, in 1985 the organisation was renamed the Defence Export Services Organisation.
DESO had an overall operating budget for 2006/7 of £51.438 million, largely covered by income received from customer governments, leaving a residue of just under £16 million provided by the British Government. For 2006/2007 it identified its priority markets as Greece, India, Japan, Malaysia, Oman, Saudi Arabia and the USA.
On 1 February 2007 it had 466 staff on its books. Nearly 400 are based in London with another 100 located in offices in 17 countries worldwide, including 65 based in Saudi Arabia. The DESO also works with military attachés based in around 80 UK embassies when necessary.