UK confirms F-35 standoff bomb buy

The Ministry of Defence has approved the procurement of the Small Diameter Bomb II as an interim standoff weapon for the F-35, months after the National Audit Office warned that funding for the capability had not been provided.

The NAO’s July 2025 report on the UK’s F-35 capability stated plainly that the aircraft lacked an effective standoff air-to-surface weapon, noting that “to acquire a more capable interim air-to-surface weapon the UK F-35 programme has requested funding for Small Diameter Bombs” but that “the MoD has yet to provide this funding.” The report further concluded that the UK had “not yet purchased an effective standoff air-to-surface weapon” for the fleet.

A letter from MoD Permanent Secretary Jeremy Pocklington to the Public Accounts Committee, dated 30 April 2026, now confirms that position has changed. Pocklington writes that “approvals have been given to proceed with a Foreign Military Sales (FMS) procurement of the precision-guided munition, Small Diameter Bomb (SDB-II),” which will provide the F-35 with an interim precision standoff capability until SPEAR-3 enters service. SPEAR-3 integration has been repeatedly delayed and is not now expected until the early 2030s.

The SDB-II is a glide weapon developed by RTX capable of engaging moving targets in all weather conditions at ranges significantly beyond those of the Paveway IV guided bomb currently carried by UK F-35Bs. It is already integrated on the F-35B and has been used operationally by U.S. Marine Corps aircraft, meaning the UK procurement does not require new integration work and can proceed relatively quickly through the Foreign Military Sales route.