Mercedes introduced the current-generation E-Class in January 2016 before giving it a mid-cycle update in March 2020. It seems just about right the three-pointed star has now been spotted testing the W214 model, unless this mule is actually for a different vehicle. The only other car that springs to mind is the next AMG GT 4-Door Coupe since the current swoopy performance saloon uses the same structure as the E63 Estate.

However, the dedicated AMG model is much newer than the E-Class, having been introduced in 2018 and about to spawn a new range-topping version with a plug-in hybrid setup dialled to approximately 800 bhp. The current GLE was launched in 2019, so the test mule is likely unrelated to the luxury SUV.

Gallery: Mercedes E-Class test mule spy photos

Assuming we are indeed looking at the next E-Class, it looks like the saloon will be getting wider tracks judging by the beefier wheel arches. That could be a clue we're looking at the mule for the All-Terrain rugged estate, but it's too early to know for sure. The "BB" in the license plate indicates the test mule belongs to Mercedes rather than a supplier, while those devices affixed to the centre of the wheels are likely related to a brake test given the sticker on the rear bumper.

Your guess is as good as ours in regards to those tiny white dots on the front fenders, with the only explanation we can find now is that those are sensors. The test mule – which uses the design of the pre-facelift model – appears to have a combustion engine since we can notice the real exhaust tips behind those finishers.

Provided Mercedes is testing the W214, the next E-Class Sedan should evolve to the prototype stage with its closer-to-production body towards the end of the year or early 2022. The reveal could take place before the end of next year, although sales are unlikely to commence sooner than 2023.