BMW M5 TOURING

Hot 5 Series-newly a PHEV - is the first to take estate form since the V10 in 2007

- MATT SAUNDERS

Dirk Hacker, vice-president and head of R&D of BMW's M division, says he loves the winding mountain roads D of North Wales, but the customs regulations that his team had to negotiate to get their prototypes here... not so much.

Autocar road testers have spent decades convincing industry people like Hacker to bring their prototypes to the UK to better tune them for the kinds of dynamic challenges their cars will face here. Now, post-Brexit, it seems that we might just as well have been inviting them to Antarctica, such are the hurdles to overcome.

However, when there's a car like the Touring version of the new BMW M5 in the final stages of development and an event like the Goodwood Festival of Speed at which to make a cameo appearance, it seems they can still be convinced. So here we are, one Tuesday in early July, in the estate version of BMW's newly plug-in hybrid 'performance exec' with some decidedly wet, tight, bumpy and slippery Welsh input to provide.

We reported track-only driving impressions on the G90-generation M5 saloon in our 26 June issue, but for those who missed that, I will recap by covering off some crucial departures and key differences that this M5 represents, compared with M5s of old and its key rivals.

This is the first car of its line to adopt electrification. There's now a 195bhp electric motor upstream of the eight-speed automatic transmission, which now has a two-speed transmission of its own. This is what the industry has come to call a P2-style hybrid powertrain (in which both the electric and combustion power sources drive through a common transmission), as distinct from the P3 kind (in which the motor joins downstream of the gearbox) currently used in Mercedes-AMG's S E Performance-branded models.