The B250e is priced from £35,280 in entry AMG Line Executive trim. This features standard kit such as the MBUX system with virtual assistance and the larger 10.2in display, heated front seats, climate control, man-made leather, 18in alloys and wireless phone charging.
Stepping up to AMG Line Premium sees the price rise to £36,780, adding the larger 10.25in digital cockpit display, augmented reality sat-nav, keyless entry and start, ambient lighting with a choice of 64 colours and an advanced sound system.
Premium Plus tops out the range at £38,280. This brings a panoramic sunroof, multibeam LED headlights, a memory function for the electric front seats and Traffic Sign assist. One stand-alone option is offered: a £1495 driving assistance package, bringing a substantial suite of advanced technology to boost safety.
The B250e joins the A250e hatch and soon-to-arrive GLA 250e crossover as platform-sharing PHEVs. The A-Class was the first to be launched, and can be had for £2300 less than the equivalent-spec B-Class.
All are powered by a 156bhp 1.3-litre four-cylinder petrol engine and an electric motor producing 101bhp. The EQ Power-badged powertrain’s combined system output is 215bhp and 332lb ft.
A 15.6kWh lithium ion battery provides the B250e with an electric-only range of 42 miles on the WLTP test cycle (down four miles on the A250e), and can be filled from 10-80% capacity in 25 minutes using a rapid charger.
A 7.4kW domestic wallbox will yield a full charge from 10% within 1hr 45min.
Performance changes over the standard A250 and B250 are minimal. The A250e will accelerate from 0-62mph in 6.6sec, 0.4sec slower than the lighter petrol variant. The B250e covers the same sprint in 6.8sec. Top speed is 146mph for the hatchbacks and 149mph for the saloon.
The new battery pack adds 150kg to the kerb weight of each car, but Mercedes says a rerouted exhaust system and repositioned fuel tank mean boot space is only slightly less than that of conventionally fuelled variants.