The engine, which has 163bhp and 280lb ft of torque, is named the dCi 165, and comes mated exclusively to Renault’s EDC automatic gearbox.
This drivetrain offers a claimed 61.4mpg and emits 120g/km of CO2 while enabling a 0-62mph time of 8.8sec and a top speed of 133mph.
When fitted to the Mégane GT Sport Tourer estate, it can manage 61.4mpg and 124g/km of CO2 respectively. The Sport Tourer is a 0.1sec slower than the hatchback from 0-62mph.
Like the petrol Mégane GT, which produces 202bhp and can hit 62mph in 7.1sec, the GT's chassis has been fettled by Renault Sport, and gets four-wheel steering to boost its agility.
The diesel GT also gets the same sporty exterior design and interior, and comes as standard with high-spec tech including a hands-free key card, dual-zone climate control and LED headlights.
There’s also a reversing camera, plus the R-Link 2 infotainment system with an 8.7in touchscreen, a DAB radio and Bluetooth.
The GT diesel costs from £27,740, making it £1300 more expensive than its faster but less frugal petrol sibling.