The company’s existing GT has been homologated to GT4 specification, but its €198,850 (about £175,000) price places it well out of the reach of most budding amateur race drivers and track day aficionados.By comparison, the Cayman GT4 Clubsport, revealed in 2015, has a starting price of €111,000 (roughly £97, 400).

“It’s a rapidly growing business segment and it is high exposure for the brand,” Autocar’s source said. “From a marketing perspective, it makes great sense, but you also need to ensure that it is financially viable in sufficient volumes and at a price to make it attractive to car buyers on a global basis. It would be additional business for AMG, not targeted at existing customers but new ones.”

A cloak of secrecy shrouds the proposed engineering of the new model, but one suggestion put to Autocar is that the Cayman rival could share certain elements with the upcoming eighth-generation SL, which is being engineered by AMG and is said to share key parts of its design with the GT. This means it would have a front-mid-mounted engine (with the unit positioned behind the front axle but ahead of the cabin), and rear-wheel drive. However, even though Mercedes-AMG has a long history of front-mid-engined performance models, insiders aren’t ruling out a mid-rear- engined layout for the new car.

Autocar’s source said: “Project One (below) represents the start of a new era for Mercedes-AMG, not only in terms of the electrified driveline but also the placement of it behind the cabin. Just how it will affect future models remains to be seen. However, a mid-rear layout is no longer taboo.”

Project One likely to be built in Britain

Although a mid-rear-engine model would arguably provide a more suitable basis for a race car than a front-mid- engined model, it would also mean the added expense and complication of engineering a dedicated platform for the car. However, this could be offset against projected sales for the new sports car, which would be expected to top those of the more expensive GT.

Porsche says it sold nearly 25,000 examples of the 718 Boxster and 718 Cayman last year. Mercedes has not quoted 2017 sales figures for the SLC, although German dealers suggest that deliveries have all but dried up and that a decision has already been made not to replace today’s seven-year-old R172 model.

Although it is not yet signed off for production, word is that Mercedes-Benz’s management board is considering plans that would enable the new AMG sports car to share selected components with the latest generation of Mercedes-Benz compact models, including the recently introduced fourth- generation A-Class.

Among the engines AMG is said to be looking at for its new model is the updated turbocharged 2.0-litre four- cylinder petrol motor.

Set to power upcoming A35 and A45 models, it would provide the AMG sports car with up to 400bhp, together with the potential for electric boosting through a belt-driven hybrid function.

By comparison, today’s 718 Cayman is sold with a base turbo 2.0-litre flat four developing 300bhp and a turbo 2.5-litre flat four with 350bhp in standard guise and 365bhp in the existing top-of- the-line Cayman GTS.