Not my own A3 that's the problem here (touch wood), but other half's '11 (61-plate) Golf VI using the 1.6 CR TDI engine that's the same used in the later A3 8P's and 8V Couldn't find an answer on the VW forums, but trying here instead.
Was driving along normally, suddenly red oil pressure symbol appeared in the DIS along with stop engine warning. Stopped as soon as I could. Whole back of the car covered in a film of oil so first thought was that the turbo had let go. No oil in the exhaust pipe, so turbo probably OK, but once it was on the tow truck could see the whole underside of the car was black with used engine oil.
Garage can't look at it until tomorrow, so for peace of mind wondering if anyone had any ideas - could be something as simple as the drain plug dropping out, but any other theories - burst oil filter, oil cooler etc? Whatever's wrong should be covered by warranty or the leasing company anyway - but would be nice to know.