The Eurostar web site now allows connections and through ticketing to select German cities using the services of DB rather than Thalys.
The cities included are Aachen, Bonn, Cologne, Dusseldorf, Frankfurt and Munich. You change in Brussels.
The fares are not totally competitive to the airlines, but it does allow some flexibility in that you can get any ICE train on to your final destination from Brussels. Some cities require two changes.
With DB not coming to London in its own right for some years, this does open up Europe (a little) for now. Fares are either in Standard or Standard Premier. I assume the connection on DB is in 2nd Class.
That is a very good travel time – CGN to LON in ~2 hours. Considering the time you spend going to the airport, airport security and sp. getting from LHR back the city, that is just unbeatable – if they adjust the fares a little they’ll be stealing customers just as the Eurostar from London to Paris is.
Cologne to London in 2 hours would indeed be phenomenal, but those times are definitely not for the whole trip. Cologne-Brussels alone is about 2 hours.
To scibuff – those timings are London-Brussels only, not including the Brussels-Cologne part of the journey – so it’s more like 4 hours minimum allowing for the connection.
Yes I fear the Eurostar web site is not really well constructed to book these tickets. However, as you can get any ICE connection, I assume they have not included the travel time beyond Brussels.