Very, very strange. The straight line from Gothenburg to County Durham followed by a 90 degree turn South could possibly be explained by a desire to shorten the over water stretch, given the lack of airfields on the East Coast between Teesside and Humberside, but even then I'm doubtful as a southerly route off the coasts of Germany and Netherlands would give more diversion possibilities. However, this routing taken by the same aircraft from Eindhoven to Finningley on 2nd Jan seems to be over water for as long as humanly possible.
https://www.flightradar24.com/data/a...r-kdm#1002e5d2