>>for christmas and allready looking for a good deal on flights<<
You don't say what dates but you're unlikely to find anything much less than 700 on scheduled flights round Xmas time...667 with Kuwait A/W about the best I've seen.
There's the Charters from Gatwick and Manchester to Phuket on a monday with fares around 400 pound but even those will go up around Xmas.
Cheap Package Holidays and Deals from MyTravel