Another tunnel, another irresistible opportunity. The roof is down, a couple of flicks of the left-hand paddle select the appropriate gear and, as we plunge into the semi-darkness, the hammer goes down. The sound is thunderous, soaring, physical, a mosh-pit heavy-metal wall of sound with a V8 bass beat. To the unsuspecting it must sound like the tunnel is caving in.

You don’t need to scare yourself silly like this to appreciate that the new 518bhp SL63 AMG firmly ticks the box marked ‘aural entertainment’. The rumble of its 6.2-litre V8 sounds great bouncing off buildings and creases your chops even at idle, the quad tailpipes emitting a spluttery, burbling pulse like a motor cruiser.