The program started originally in June 2000, when Racal Defence Electronics won a Ministry of Defence tender to conduct the 12 month assessment phase of the SENDER Tactical Unmanned Aerial Vehicle program. SENDER was defined as a Tactical UAV System, which will provide real-time battlefield intelligence to the British Army, to meet unit level
Intelligence, surveillance, target acquisition, and reconnaissance requirements. The next phase of the program was initiated to support an operational need, which was identified at the start of the
War in Afghanistan, to provide the UK Armed Forces with all-weather day and night surveillance capability. In February 2003, the Ministry of Defence announced that two contenders reached the final stage of the tender, a group that includes Thales (at the time still operating under the name
Racal Electronics) and Elbit Systems, and a second contender
Northrop Grumman, after
BAE Systems and
Lockheed Martin were deselected (BAE subsequently entered negotiations to join forces with Northrop for the bid). Thales and Elbit won the tender in July 2004, and proposed to build UAVs based on Elbit Systems' Hermes 180 and Hermes 450, which will be delivered to the British Army between 2006 and 2009. In August 2005 the program agreement was signed, at a cost of £700 million. The tender condition included a requirement to set up a local manufacturing facility for the program, Additionally, in October 2005, a flight testing facility was inaugurated at
ParcAberporth in West
Wales, with a test flight of an Hermes 450. In June 2007, the joint venture company UAV Tactical Systems, was awarded a $110 million contract to provide an urgent intelligence, surveillance, target acquisition and reconnaissance support capability for the British Army, in Iraq and Afghanistan, using Hermes 450 UAVs leased from Elbit systems (and not using any Watchkeeper WK450, that was still in development). On 15 July 2007, the
UK MoD revealed that 54 Watchkeepers would be delivered to the
British Army at a cost of £800m. This figure includes construction of new basing facilities at
Boscombe Down airfield, ground training facilities and simulators at the School of Artillery, ground control stations, development and testing of extensive aircraft modifications including automatic take-off and landing and the integration and provision of new sensors including radars. In October 2008,
Rosh Pina Airport in Israel was used for flight trials of the Watchkeeper, after Britain had objected to the trials being conducted at
Fik Airfield, Elbit's test site, which is in the
Golan Heights. Watchkeeper's first UK flight took place on Wednesday 14 April 2010 from
ParcAberporth in Wales, but due to numerous delays the delivery date slipped. By 2014 Watchkeeper had gained certification from the
Military Aviation Authority, had its Release to Service granted was cleared for military flight training with the
Royal Artillery, operating out of Boscombe Down in Wiltshire. In February 2014 the
French Ministry of Defence indicated that the
French Army might purchase the Watchkeeper WK450, but they instead selected the
Sagem Patroller in 2016 for the tactical unmanned air vehicle requirement. By December 2015 delivery to the British Army was progressing well, but there were difficulties in training sufficient pilots. As poor weather in Britain was limiting the time available to conduct flying training the decision was made to conduct future training on the tropical
Ascension Island located in the Atlantic Ocean. Although there is hope that future modifications to the aircraft will enable it to fly in poor weather, the training on Ascension Island is set to continue for the foreseeable future. Enough pilots and ground crew are expected to be trained for full operational capability to be reached by early 2018. Costs of the programme to March 2018 were £1.08 billion, more than £200 million above the original budget. The original order was for 54 Watchkeepers, though it has not been confirmed that more than 45 had been delivered at that date. A report by the
Major Projects Authority, published in June 2015, revealed that the estimated cost of achieving full operational capability of the program is £1.2bn. Watchkeeper achieved the Army's full operational capability 2 (FOC 2) milestone on 30 November 2018, though without formal release to service (RTS) certification, which would allow the trials facility to move from
West Wales Airport, which has a nearby oversea trials area, to Boscombe Down. Full clearance to service was made in April 2019. In June 2023, Defence minister
James Cartlidge stated that the Watchkeeper program had cost £1.35 billion to date, including necessary airfield upgrades at
Aberporth and
Boscombe Down. By 2023, one in seven Watchkeepers had been lost, giving concerns about the cost-effectiveness of the Watchkeeper compared to smaller more modern UAVs. In November 2024, Defence Secretary
John Healey announced to the UK
House of Commons that some military equipment, including the entire fleet of Watchkeeper WK450 Mk1 drones, would be retired earlier than planned to cut costs. In January 2026,
Elbit Systems announced the completion of the acquisition of Thales UK's remaining 49% stake in UAV Tactical Systems (U-TacS). This transaction concluded the long-standing joint venture between the two companies, with U-TacS becoming a wholly owned subsidiary of Elbit Systems UK. In June 2018 a Watchkeeper crashed on land near the trials base at
West Wales Airport, increasing the number of Watchkeepers lost in crashes to five. units that had crashed in the UK were WK031 - 16 October 2014, WK006 - 2 November 2015, WK042 - 3 February 2017, WK043 - 24 March 2017, and WK050 - 13 June 2018. Links to the enquiries are available at the Army Watchkeeper Web page. Watchkeeper proved its use by successfully supporting a detachment of
U.S. Marines using its Thales I-Master radar. It cued a
Hermes 450 onto a target for continued tracking, which then passed the information on to a
Royal Air Force MQ-9 Reaper to conduct an airstrike. Some 140 flights were conducted for 8 hours a day until operations ceased in mid-October 2014.
Border patrol In September 2020, in support of the
UK Border Force under Operation Deveran, the British Army used Watchkeeper to patrol the
English Channel for potential illegal entrants into the UK. The operation was criticised as being of little practical value. Just 15 sorties, totalling 43 hours and 52 minutes, were flown in September 2020, and six sorties for 23 hours and 54 minutes were flown the following month. Chris Cole, director of Drone Wars UK, said "the use of military-grade drones at borders is the beginning of the use of drones that blur the boundaries between military and domestic policing".
Replacement Project Corvus was initiated in April 2025 to replace Watchkeeper UAVs, with a budget of £156 million for five years of operation, planned to start in 2026. One analyst writing for the
Royal United Services Institute did question if
medium-altitude long-endurance UAV (MALE) drones, like the Watchkeeper and its replacement, are survivable in the threat environment of contemporary conflicts, pointing to the lack of success of Ukraine's
Bayraktar TB2 fleet and the loss of 15 US
MQ-9 Reaper UAVs over Yemen. ==See also==