The closest real snow centre is Hemel Hempstead's The Snow Centre (The Snow Centre - Ski Lessons) or Milton Keynes Snozone (Indoor Skiing & Snowboarding Milton Keynes & Castleford). read more
If you just want skiing and not an actual ski resort, then the nearest is one of the indoor slopes - such as Chel-Ski which Is in Chelsea central London. Otherwise it would be France, and somewhere like La Clusaz or Flaine would be the most convenient. read more
Flights to Oslo from London, Manchester, Birmingham or Edinburgh take around one hour, 45 minutes and the capital has a great little ski area at Tryvann up on the hill above. You can reach there in 58 minutes by a combination of fast airport train, tram and a short shuttle the last mile or in 48 minutes by a rather more expensive taxi or rental car. read more