DB tested their new trains (they were on show at St Pancras) which will be used on the London - Amsterdam/Frankfurt routes last month. You can already buy pretty cheap tickets from London to German locations on the DB web page (Special London Ticket or something) and use DB tickets to board. So the integration is happening quite quickly. I hope it doesn't take 5-10 years.
DB tested their new trains (they were on show at St Pancras) which will be used on the London - Amsterdam/Frankfurt routes last month. You can already buy pretty cheap tickets from London to German locations on the DB web page (Special London Ticket or something) and use DB tickets to board. So the integration is happening quite quickly. I hope it doesn't take 5-10 years.