DSEi Defence Security and Equipment International ( DSEi ) is a defence and security equipment exhibition held every two years in London Docklands , which draws thousands of visitors , both trade and military . It is an important event in the international military and national security equipment sales calendar and is organised in association with UK Trade & Investment ' s Defence & Security Organisation ( UKTi DSO ) . It is the world ’ s largest fully integrated international defence exhibition featuring land , sea and air products and technologies . In 2007 DSEi confirmed its position as one of the leading defence systems and equipment trade events in the world with 1350 exhibitors from 40 countries . It is a “ tri - service ” defence and security exhibition , meaning it showcases military equipment for all kinds of land , sea and air needs . DSEi ' s history . Between 1976 and 1991 , the British Army Equipment Exhibition and the Royal Navy Equipment Exhibition were held on alternate years in Aldershot and Portsmouth respectively . Overseas delegations attended by invitation only , but those invited often included governments with such poor human rights records as Indonesia and Chile . Despite having been at war with Iran for almost six years , a five - strong delegation from Iraq attended in 1986 . In 1993 the two exhibitions were combined and held every other year until the British government decided to privatise the exhibition . Exhibitions company Spearhead launched the first DSEi , then known as Defence " Systems " and Equipment International , in 1999 at Chertsey in Surrey . In 2001 it moved to its current location at the ExCeL Exhibition Centre in London Docklands . DSEi ' s name was changed in 2009 , replacing the word " Systems " with " Security " . Current ownership . In April 2008 DSEi was acquired by Clarion Events , the largest independent event organiser in the UK . At the same time Clarion also acquired ITEC - a conference and exhibition dedicated to military simulation , training and education - and Latin American Aerospace and Defence . It was suggested by CAAT ( Campaign Against Arms Trade ) that former owners Reed Exhibitions ' decision to sell followed substantial criticism both from healthcare professionals and academics , as well as pressure from campaigners . Political controversy . DSEi works closely with UKTi DSO to invite foreign military delegations . Some of the nations attending have been accused of human rights violations , leading to concerns over their involvement . Defence exhibitions such as these have also been accused of furthering intra - and international conflicts by providing the weapons used . Protests . The event has attracted much attention from activist groups . The fairs in 2001 , 2003 , and 2005 were all targets of sizeable protests . Former London Mayor Ken Livingstone has been critical of the event and even the Metropolitan Police have spoken out about the cost of policing the event . 2003 . At DSEi 2003 , 54 people were arrested around the site . 2 , 600 security guards and police officers were guarding the site . Scotland Yard spent £1m on policing the event . The police were granted permission by David Blunkett , then Home Secretary , to use special powers under the Terrorism Act 2000 against protesters at the fair . The grant was criticised by Liberty and opposition politicians . DSEi 2005 . DSEi 2005 was held from 13 to 16 September . It was 30 % bigger than 2003 ' s event , and in addition to traditional military systems & equipment , displayed " products and services related to Homeland security , anti - terrorism , access control , and personal security . " DSEi 2007 . DSEi 2007 was held on 11 – 14 September at the ExCeL centre . The Space Hijackers protest group managed to successfully drive a tank up near to ExCeL after distracting police with a decoy vehicle . The tank was then " sold " to the highest bidder in a mock auction outside the fair in front of the press in order to highlight the lack of controls over the arms trade . DSEi 2009 . DSEi 2009 was held 08 - 11 September 2009 at the ExCeL centre . DSEi 2011 . DSEi 2011 was held 13 – 16 September 2011 at the ExCeL centre , and was attended for the first time by a Type 45 destroyer , .