"ALICANTE HERE WE COME!"

The contrail is from a Primera Air Scandinavia flight from Reykjavik to Alicante just west of Glasgow as the sun was going down. For any anoraks amongst us it's a Boeing 737 at 39,000 ft., travelling at just over 450 knots and due to arrive Alicante at 11 minutes past midnight their local time (at least according to the amazing Flightradar24 app.)
Also a very pleasant sky for those looking down and us looking up :-)