The new BMW i3 – the electric 3 series – will be offered in Touring estate form, and Autocar's spy photographers have caught it testing for the first time.

Although the prototype's rear end is disguised, it appears to be longer than the i3 saloon, with a sloped roofline. 

The new images come after a silhouette of the i3 Touring was shown during the saloon's unveiling.

"Business customers and families will be particularly delighted: the Touring has always been a favourite with them," said then BMW Group chief Oliver Zipse. 

The current petrol 3 Series has 480 litres of boot space as a saloon and 500 litres as an estate. BMW has yet to publish a capacity for the new i3, but it's expected to offer substantially more space.

However, it doesn't appear to reprise the unusual split tailgate – in which the rear window alone can be opened to provide easier access to the boot – that featured on previous Touring versions of the 3 Series.

The i3 and related iX3 SUV are the first models of BMW's Neue Klasse era – a complete rethink of how it designs and engineers cars for the EV age, inspired by the original Neue Klasse cars that brought the brand into the mainstream 60 years ago.

The i3 saloon is among the UK's longest-range EVs, officially allowing drivers to cover 567 miles between charges. It remains to be confirmed how the Touring conversion will affect this, but the poorer aerodynamics are expected to reduce the figure slightly.

The estate is expected to be slightly more expensive than the saloon, which starts at £53,005.