Originally Posted by
railways
DB tickets are priced on the basis of the ICE you take from Brussels, not the Eurostar. Therefore, the price differential tends to be highest if you book on the Sunday early morning ICE from Brussels (low demand) and you want to take a Friday afternoon (high demand) Eurostar from London-Brussels.
Just noticed that a ticket for my London-Germany journey, which I bought weeks ago, is still priced at €49. This is for a departure between Christmas and New Year. For the same London-Brussels train, Eurostar is pricing out at £140.