UK defence secretary Gavin Williamson has signed a $1.98bn (£1.51bn) deal to purchase five Boeing E-7 Wedgetail aircraft. The E-7 fleet will replace the current E-3D Sentry aircraft in perfoming the UK’s Airborne Early Warning and Control (AEW&C) mission.

In announcing the deal, Williamson emphasised that it would help to strengthen the UK's partnership with Australia, which operates a fleeet of six Wedgetails, delivered between 2009 and 2012. The armed forces of both countries will also operate the F-35 and Type 26 warships, as well as the P-8A Poseidon maritime patrol aircraft.

As part of the plan for a managed transition to E-7, the UK is to reduce the existing E-3D fleet from six to four aircraft by removing the two long-term unserviceable assets from the active fleet. This will enable the Sentry Force to focus resources on providing better availability from the remaining four aircraft, Williamson said, in order to better assure the future Sentry Fleet output, including UK commitments to the NATO Airborne Early Warning and Control Force and the provision of NATO Assurance Measures missions.