BMW's key fleet model, now in its seventh generation, is expected to provide the highest levels of efficiency and driver engagement in its segment.
Priced from £33,610, the new 3 Series will be on sale from March 2019 and features new connected services and technology such as an NFC smartphone key.
It weighs up to 55Kg less than the outgoing model, making it more economical and better to drive. A longer wheelbase provides greater interior space.
The full engine line up is yet to be confirmed but BMW has published fuel economy data for the 320d, which can achieve up to 67.3mpg.
CO2 emissions start from 110g/km for the diesel, giving the the new 3 series an edge over its rivals. There will also be a 330e plug-in hybrid, which is likely to emit less than 50g/km.