GTM Cars
Corporate brand
UnclaimedGTM Cars was a British manufacturer of mid-engined component and kit sports cars derived from Mini and other donor-car components.
Last updated August 25, 2026
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Overview
GTM Cars was a British specialist sports-car marque and kit-car manufacturer whose products were aimed at enthusiasts willing to assemble a lightweight, mid-engined vehicle from a component package or buy a factory-built example. The company began in 1967 when Bernard Cox and Jack Hosker created the Cox GTM, short for Grand Touring Mini. The compact sports car used Mini components in a mid-engined layout and quickly attracted interest from the British kit-car community. Initial production took place on a small scale in a garage in Hazel Grove, Stockport, with approximately 50 kits completed before Cox withdrew from production in 1968. Howard Heerey, who had raced a GTM, and his father then took over the project. They simplified the name to GTM and continued development of the design. By 1971, roughly 170 kits had been produced, with the car evolving through several iterations identified as GTM 1-3. Production stopped in 1972 after road-widening work affected the company’s premises. The moulds, jigs, demonstrator and remaining spares subsequently passed through several owners. A Hartlepool fibreglass company acquired the project but did not produce cars, while KMB Autosports later concentrated on supporting existing vehicles rather than restarting kit production. The marque entered its most productive period after Peter Beck, Paddy Fitch and Dougal Cowper acquired it in 1980. Cowper left relatively early, while Beck and Fitch developed GTM into a more substantial specialist manufacturer. The business moved to Sutton Bonington in 1982 and spent the following two decades refining the GTM Coupé and introducing additional models. The Mini-based Rossa brought a more contemporary body style, followed by the Rossa Mk2. GTM’s adoption of Rover’s K-series engine in the third-generation Rossa created the K3, one of the earliest production sports cars to offer the engine in a mid-mounted configuration. The same basic engine concept later appeared in better-known specialist vehicles including the Lotus Elise, MG F and Ariel Atom. GTM expanded beyond its compact Mini-derived cars with the Libra, designed by Richard Oakes and introduced in 1998 after a three-year development programme. The Libra was positioned as a more upscale sports car, while the Spyder, launched four years later, offered an open-top body with related styling but limited panel commonality. Both models could be supplied either as kits or as complete factory-built cars, reflecting GTM’s hybrid position between a component supplier and a low-volume vehicle manufacturer. RDM Group acquired GTM Cars in 2003, and the company moved to Coventry in 2004. Under RDM, GTM explored the Ballista, a revised version of the Larini kit based on Volkswagen Golf Mk2 components, and the 40TR, a skeletal track-focused vehicle using the Spyder’s fibreglass monocoque tub. Neither project progressed into regular production, and the Libra and Spyder remained the principal offerings. In December 2007, the company was acquired by Potenza Sports Cars, the parent of Westfield Sportscars. GTM displayed a redeveloped 40TR at the 2008 Autosport Show and appeared at the 2009 National Kitcar Show with a Spyder demonstrator. Potenza indicated that future cars would be branded Westfield GTM rather than marketed as an independent marque. In January 2010, Westfield Sportscars announced that it was no longer offering the existing GTM range because of parts-procurement problems, while also stating that it intended to design and manufacture a new GTM over the following year. No subsequent production revival is documented in the supplied reference material, so GTM Cars is treated as defunct or inactive.
History
GTM Cars originated in 1967 when Bernard Cox and Jack Hosker built the Cox GTM, a compact mid-engined sports car using components from the Mini. The name represented Grand Touring Mini. The first examples were assembled in a garage in Hazel Grove, Stockport, and demand was sufficient for the partners to produce kits as quickly as their limited facilities allowed. Cox ended production in 1968 after approximately 50 kits had been made. Howard Heerey, an owner and racer of a GTM, and his father acquired the project and continued it under the shorter GTM name. The design progressed through several revisions, reaching the GTM 1-3 specification by 1971. Approximately 170 kits had been produced by that point. Production ended in 1972 when road-widening work affected the road outside the company’s premises. A fibreglass manufacturer in Hartlepool subsequently purchased the demonstrator, moulds, jigs and spares, but did not restart production. KMB Autosports acquired the project in 1976 and supported existing cars with parts, although it did not build new kits. A major revival began in 1980, when Peter Beck, Paddy Fitch and Dougal Cowper acquired GTM. Cowper departed relatively soon afterward, while Beck and Fitch developed the company into a more durable specialist manufacturer. The business moved to Sutton Bonington in 1982. During the next two decades, GTM refined the GTM Coupé and added several models. The Rossa retained the Mini-based mechanical concept but used more modern styling, followed by the Rossa Mk2. The third-generation Rossa was fitted with Rover’s K-series engine and marketed as the K3. Its mid-mounted K-series installation made it an early example of a production sports car using that engine layout, preceding or anticipating similar applications in other British specialist vehicles. GTM broadened its range in 1998 with the Libra, designed by Richard Oakes after three years of development. The model was intended as a more upmarket sports car. Four years later, the company introduced the Spyder, a convertible with related styling themes but relatively little shared bodywork with the Libra. Both were available as kits or as complete factory-built cars, allowing GTM to serve both traditional home-build customers and buyers seeking a finished vehicle. RDM Group bought GTM Cars in 2003. The company moved to Coventry in 2004 and developed the Ballista, a modestly revised Larini design based on Volkswagen Golf Mk2 components, together with the 40TR, a skeletal track car using the Spyder’s fibreglass monocoque tub. Neither project reached regular production. GTM therefore continued to rely principally on the Libra and Spyder. In December 2007, Potenza Sports Cars acquired GTM. Potenza also owned Westfield Sportscars, and GTM subsequently appeared on Westfield-related exhibition stands. A redeveloped 40TR was shown at the 2008 Autosport Show, while a Spyder demonstrator was displayed at the 2009 National Kitcar Show. The company stated that its cars would be rebranded Westfield GTM, reducing GTM’s identity as an independent marque. In January 2010, Westfield announced that parts-supply problems had led it to withdraw the current GTM range, although it said that a new GTM might be designed and manufactured over the following year. The available reference material does not document a later production restart.
- 2010
Existing range withdrawn
[1]Westfield announced that parts-procurement problems had ended sales of the current GTM range.
- 2007
Acquisition by Potenza Sports Cars
[1]Potenza Sports Cars acquired GTM in December.
- 2004
Move to Coventry
[1]GTM relocated to Coventry under RDM ownership.
- 2003
Acquisition by RDM Group
[1]RDM Group purchased GTM Cars.
- 2002
Spyder introduced
[1]GTM followed the Libra with the Spyder convertible.
- 1998
Libra introduced
[1]GTM launched the Richard Oakes-designed Libra after a three-year development programme.
- 1982
Move to Sutton Bonington
[1]GTM relocated to Sutton Bonington as it developed the Coupé and later models.
- 1980
GTM enters its main growth period
[1]Peter Beck, Paddy Fitch and Dougal Cowper acquired GTM and restarted its development as a specialist manufacturer.
- 1976
KMB Autosports acquires the project
[1]KMB Autosports acquired GTM assets and concentrated on spares for existing cars.
- 1972
Production closes after premises disruption
[1]Road-widening work outside the garage forced the company to stop producing kits.
Products and positioning
A British enthusiast-oriented specialist positioned around lightweight, mid-engined sports cars available in kit or limited factory-built form.
Kit sports car · 1967
Cox GTM
The original Grand Touring Mini was a compact mid-engined sports car designed by Bernard Cox and Jack Hosker. It used Mini components in a lightweight kit-car package and established GTM’s basic engineering identity. Early production was carried out in a garage, with approximately 50 kits completed before the original production run ended.
Kit sports car
GTM Coupé
The Coupé was the central product of GTM’s revival period after 1980. It developed the original compact, mid-engined concept into a more refined enthusiast car and served as the foundation for later derivatives. The model was offered in the British specialist-car tradition, where customers could assemble a component package or obtain a complete vehicle.
Kit sports car
Rossa
The Rossa was another Mini-based GTM model, distinguished by more contemporary styling than the earlier cars. It was followed by the Rossa Mk2 and later by the K3 derivative. The range helped GTM maintain its focus on compact, accessible, mid-engined sports cars while modernising the exterior design.
Mid-engined kit sports car
K3
The K3 was the third-generation Rossa equipped with Rover’s K-series engine. Its mid-mounted K-series configuration was an important technical distinction and placed GTM among the early specialist manufacturers to use the engine in that layout. The car continued the marque’s lightweight, component-car approach while moving beyond its earlier Mini-based mechanical specification.
Upscale sports car · 1998
Libra
Designed by Richard Oakes, the Libra was introduced in 1998 after three years of development. It represented GTM’s attempt to move into a more sophisticated and upmarket sports-car segment while retaining the company’s low-volume, mid-engined specialist identity. The Libra could be purchased as a kit or as a complete factory-built car.
Convertible sports car · 2002
Spyder
The Spyder was GTM’s open-top model, introduced four years after the Libra. It shared some styling cues with the Libra but used comparatively few common body panels. Like the Libra, it was available in both kit and factory-built forms and remained one of GTM’s principal products during the RDM and Potenza ownership periods.
Development kit car
Ballista
The Ballista was a planned minor reworking of the Larini kit-car design, based on Volkswagen Golf Mk2 components. RDM Group developed the concept after acquiring GTM, but it did not progress beyond development into a regular production model.
Track car
40TR
The 40TR was conceived as a skeletal, track-oriented vehicle using the fibreglass monocoque tub of the Spyder. It remained a development project rather than a documented series-production model. A redeveloped version was displayed at the 2008 Autosport Show after earlier development work had been deferred in favour of the Ballista.
Brand decisions
2010
Withdrawal of the current GTM rangeStrategyBackground
The Libra and Spyder remained the principal GTM models, but the business faced difficulties obtaining the parts required to supply them.
Action taken
Westfield Sportscars announced in January that it was no longer offering the existing GTM models because of parts-procurement problems.
Aftermath
Westfield stated that it intended to design and manufacture a new GTM during the following year, but the supplied reference material does not document a subsequent production restart.
2009
Planned transition to Westfield GTM brandingStrategyBackground
After Potenza’s acquisition, GTM continued to have a small presence at kit-car events, including a Spyder displayed at the 2009 National Kitcar Show.
Action taken
Potenza indicated that the cars would be rebranded Westfield GTM instead of being marketed as a separate GTM marque.
Aftermath
The change suggested an integration of GTM into Westfield’s portfolio rather than a continuation of GTM as an independent brand.
2007
Potenza Sports Cars acquisitionM&ABackground
GTM had been owned by RDM Group since 2003, but the business remained a small specialist manufacturer with a limited model range and several uncompleted development projects.
Action taken
Potenza Sports Cars acquired GTM Cars in December 2007. Because Potenza also owned Westfield Sportscars, GTM was subsequently presented alongside the Westfield business.
Aftermath
GTM vehicles were discussed for rebranding as Westfield GTM, weakening the marque’s independent identity. The existing range was later withdrawn in 2010.
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