The first member of the Bentley Mulliner Coachbuilt portfolio - the Bacalar - has started its final test, development and durability work ahead of the build of 12 pre-sold customer cars due to start build next year.

Bacalar Car Zero, a purpose-built engineering prototype and the first barchetta-style Bentley of the modern era, is already accumulating mileage and passing crucial quality tests at a variety of locations around Europe.

The on-car validation programmes have been condensed into an extremely busy schedule covering 20 weeks. So far, the car has completed wind tunnel-based aerodynamic assessment, high speed stability and top speed testing, handling and dynamics evaluations, appraisal of noise and vibration, and careful thermal measurements.

The car now enters a period of ongoing customer-focused mileage accumulation and durability work, before a phase of climate cycle testing up to 80 degrees Celsius and an intensive electrical system validation.

All of this work is vital to sign-off the new and bespoke nature of the Bacalar - the car includes a total of more than 750 new components, all of which have to pass Bentley's exceptionally stringent quality, functionality and durability standards. More than 40 of those parts are crafted in carbon fibre, while a complement of nearly 100 are produced using rapid additive manufacture techniques.

Just 12 examples of this striking, limited edition model are being created, guaranteeing rarity and exclusivity, and offering supreme luxury and breath-taking performance. A roofless Barchetta design with all new and highly muscular coachwork, embracing a myriad of options and materials, each Bacalar will be truly unique, the result of direct interaction between the Bentley Mulliner design team and the individual customer.

A masterpiece of craftsmanship, the Bacalar is a seamless fusion of materials with an intelligent curation of technology. It draws on design DNA and materials inspiration from the beautifully sculpted, award-winning EXP 100 GT.

Materials include paint containing ash from rice husks, which provides a sustainable way of delivering a rich metallic finish, as well as the use of natural British wool and 5,000-year old Riverwood sourced from the ancient Fenlands of East Anglia.

The Bacalar features an enhanced version of Bentley's 6.0-litre twin-turbocharged W12 engine, producing 650bhp and 900Nm of torque, mated with an advanced Active All-Wheel Drive System that varies the torque split between the front and rear wheels.

It allows the Bacalar to use rear-wheel drive as much as possible during normal driving for optimum efficiency and dynamic performance. The drivetrain is at the heart of the Bacalar, creating the ultimate open-air, two-seat luxury Grand Tourer available in the world today.

With the Bacalar, customers have had the ability to work closely with a team of specialist designers to enhance their vehicle with a selection of unique materials and specially curated options. The Bacalar is the first - but other new bespoke Bentleys will follow as part of the Bentley Mulliner Coachbuilt portfolio - one of three divisions of the Bentley Mulliner organisation, alongside Classic (delivering the Blower Continuation Series) and Collections (responsible for the Continental GT Mulliner coupe and convertible).

The Bacalar shares no body panel with any other car in the Bentley model lineup and derives inspiration from the dramatic EXP 100 GT concept car conceived to mark Bentley's centenary last year. Also, it only shares one exterior component with a Continental GT - the door handle, simply because it contains the keyless entry system.

The rear clamshell, wings and top deck of the Bacalar are crafted from carbon fibre, while the doors are lightweight aluminium. Combined with the use of three-dimensional printing, it has allowed designers to create an even more distinctive car.

The exterior look of each model is completed in collaboration with individual customers, who have been able to further personalise their car, choosing from rare paint options, exterior treatments and design themes. The Bacalar represents a return to the exciting early years of Bentley, allowing owners to help shape the car of their dreams.