Increased fuel consumption

[Andy c stanley]

210000 miles. Full service. Just passed mot. Unfortunately has bmw engine. Runs on super diesel but fuel consumption is dramatically increasing but drives fine. 

[avensis_2018]

a car, any car, if you just drive it with mot 1 a year, its goes only to one direction = down.

you need to do a preventing maintenance from time to time cleaning sensors\filters, changing oil more frequency, tyers, allayment of the wheels  and some more, if not, you can just drive it like most of the people but, it wont stay its just going down all the time, wear + time finish the car you need to make it runs the best also give you better feeling while you drive it also fuel consumption.

or you can just drive it and fix it when it stops, after 2-3 years buy a new car and again ....

enjoy.

[ToyotaFanDriver]

Since you mention its a diesel, be aware that winter diesel starts coming into the fuel pumps around this time of year. The formulation is different to cope with the colder temperatures and so it gives slightly lower mpg.

[TonyHSD]

Preventative maintenance is everywhere. 
Usually with age and mileage the fuel,consumption should not increase dramatically if the car been sensibly used and properly maintained. 
BMW engine has timing chain that needs replacement every 150000 miles. 
This could be the answer to the high fuel consumption, if timing it’s not right.