I’m both impressed and eating a fair portion of humble pie about the E-Class’s Attention Assist system.

It’s designed to detect drowsiness, and uses sensors monitoring 70 parameters including steering, accelerator and brake inputs, time of day, weather and time behind the wheel without a break.

I’ve been a bit cynical about systems like this, especially after one long drive when I felt it should have kicked in before I took a break. However, a recent late-night trip to Yorkshire set it off after I considered a stop unnecessary because I was feeling alert. A cacophony of visual and aural signs soon prompted a reassessment that led to me swapping driving duties with the better half.

Most drivers have been in that situation, and will be inclined to just trust their own judgement and the devil whispering in their ear, but having an automated angel perched on the other shoulder could make all the difference and head-off fatigue-related accidents.

Mercedes-Benz E250 CDI Avantgarde manual
Mileage 9984
Claimed combined
Our average consumption 39.0mpg
P11D price £32,545
Model price range £27,570-£73,855
CO2 (tax) 142g/km (20%)
BIK 20/40% per month £108/£217
Service interval variable mls
Insurance group 38
Warranty 3yrs/unlimited mls
Boot space 540 litres
Engine size/power 2143cc/204PS
Top speed/0-62mph 149mph/7.7secs
Why we’re running it To see if it can take on the
excellence of BMW and
Jaguar in this sector
Positive Comfort, quality,
standard features
Negative Manual gearbox