I once travelled on a 159 from Basingstoke direct to Paddington. This was in the early 1990s, a bomb scare had shut the SW main line at Brookwood, so nothing was running beyond Farnborough. The train I got was a scheduled Salisbury to Waterloo, but was diverted at Basingstoke to travel into Paddington. We stopped at Reading as well- I presume this would have been to pick up a route conductor rather than passengers- then travelled up the relief line into Paddington. I remember the announcement on arrival as well "we apologise for your arrival at London Paddington this morning" :grin:
Incidentally, with reference to the thread over in the "rolling stock" forum, the 159 did have "Paddington" on its destination screen as well
Wonder if this would happen in today's privatised world....