Marshall Aerospace and Defence Group

Marshall has been fixing and modifying aircraft in Cambridge since 1909, when David Gregory Marshall started with cars and moved into aviation. The family holding company kept the aerospace business through a run of disposals that reshaped the group in 2025. Slingsby Advanced Composites went to a Swedish buyer in June of that year and Marshall Land Systems, the deployable shelter and vehicle engineering arm, was sold to Flowing River Capital in November. What is left is an aerospace business of roughly two thousand people organised around maintenance, repair and overhaul, engineering services and precision manufacturing, still looking for a permanent home to replace Cambridge Airport before its lease runs out at the end of the decade, and reported in 2026 to be exploring a sale of its own.

The MRO line is the anchor. Marshall has worked on the Lockheed Martin C-130 Hercules since 1966 and became the first authorised C-130J Heavy Maintenance Centre outside the United States, with authority to manufacture parts and recognition as a centre of excellence for centre wing box replacement. That is unglamorous, difficult work. Cutting a wing box out of a transport aircraft and putting a new one in is closer to shipbuilding than to line maintenance, and few organisations anywhere are cleared to do it. Customers include the Royal Air Force, a joint Danish, Norwegian and Dutch C-130J arrangement that was extended again in 2026, and the Turkish Ministry of National Defence, which contracted Marshall in 2025 to bring twelve former UK C-130J aircraft into service and sustain them.

Engineering services covers the modification side. Marshall designs capability upgrades, runs certification and flight test, and manages airworthiness for operators who do not carry that competence in house. Its Adaptable Role-fit Capability family started with ARC Radar, a palletised sensor fit that turns a tactical transport into a surveillance aircraft using a two-panel Leonardo Osprey 30 AESA radar, conformal radomes built into modified paratroop doors, an equipment rack and a mission console. Nothing is permanently cut into the airframe and the whole installation goes in or comes out in under four hours. The same team has fitted aerial refuelling probes, palletised medical evacuation kit and cargo handling equipment to transport types.

Precision manufacturing supplies parts rather than services. Marshall has been Boeing's exclusive supplier of auxiliary fuel tanks for the P-8 Poseidon since 2005, shipping them in sets of six per aircraft and passing twelve hundred units in total, a long production run that also carries the aerostructures and complex subsystem assembly work the group sells to other primes. Component repair, refurbishment and supply chain management round out the offer. The customer list runs to governments, aircraft manufacturers and prime contractors rather than airlines, and the C-130 remains the platform the company is known for.