On July 11, the United Kingdom’s National Audit Office revealed in one of its latest reports that the development of the new Spear 3 cruise missile—intended to arm its F-35B fighters—is facing delays, along with the aircraft’s Block IV upgrade package. In light of this situation, the British Ministry of Defence is reportedly interested in equipping its stealth fighters with RTX GBU-53/B glide bombs, also known as StormBreaker, to enhance the aircraft’s strike capabilities while the aforementioned delays are resolved.
Expanding on the details, it’s worth noting that Spear 3 missiles were originally expected to begin entering service aboard the F-35Bs by December 2024. However, according to estimates published in the report titled “The UK’s F-35 capability,” that timeline has now been pushed back significantly, possibly into the early part of the next decade. Meanwhile, integration tests with the Meteor beyond-visual-range air-to-air missile—an already developed weapon—are awaiting approval from the F-35 Joint Program Office to access testing aircraft and facilities.
As for the reasons behind the Spear 3 program delays, the report states that the missile’s supply chain has suffered from poor performance due to a shortage of qualified and experienced personnel for this type of project. Additionally, delays in the delivery of key components manufactured in the United States have further impacted the timeline. Looking ahead, the UK may only receive an initial, limited batch of the missiles in the medium term.
Regarding mitigation efforts, the report notes: “The MoD has not fully mitigated the capability risk caused by these delays. As interim measures it uses alternative weapons. Paveway IV is currently the primary air-to-surface weapon and the AIM-120D the primary beyond visual range air-to-air weapon. But Paveway IV lacks the range to be an effective standoff weapon. This means that UK F-35 aircraft cannot currently perform all missions against ground-based targets at a safe distance.”
Specifically addressing the StormBreaker bomb that the UK is seeking to acquire, the report adds: “To acquire a more capable interim air-to-surface weapon the UK F-35 programme has requested funding for Small Diameter Bombs. The MoD has yet to provide this funding. The AIM-120D will effectively mitigate the capability risk of delays to Meteor integration, as long as they are available in sufficient numbers.”
For now, reviewing the characteristics of the weapon system the UK is aiming to integrate with its F-35Bs, the StormBreaker is a smart glide bomb originally designed for the U.S. Air Force. Each unit features an advanced tri-mode seeker combining infrared imaging and millimeter-wave radar, enabling it to strike targets with precision even in adverse weather conditions. It has a range of up to 72 kilometers. Additionally, according to the manufacturer Raytheon, StormBreaker can be launched from one platform and controlled from another, offering enhanced operational flexibility.
Images used for illustrative purposes only.
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