"Nightstar" started testing in August 1996 with regional services planned overnight through the Channel Tunnel. See
(here) on Wikipedia. But it was not to be
The 139 carriage stock order began construction in 1992 and continued slowly until the whole project was put on hold in 1997, then formally abandoned in 1999. The reasons for the delay in the start of operations and then the final cancelling of construction are similar to those given for the non-start of Regional Eurostar service: primarily due to rising costs and competition from low-cost airlines such as Ryanair and EasyJet.
and
In retrospect, the service was ill-conceived. So many trains to various destinations would probably have been poorly used, and security at some stations would have been expensive, because security-cleared international travellers would have needed to be separated from local passengers. Eurostar also neglected the core routes from London to Paris and Brussels, claiming these were not needed because of the short journey time, but overlooking that morning meetings otherwise require an overnight stay or a very early start. A late night departure and early morning arrival on the London to Paris/Brussels/Amsterdam/Cologne axis, with internal connections elsewhere, would have had better potential.
Security issues aside (and they are considerable) I have to wonder if the Nightstar was an idea ahead of its time. With new environmental concerns, is there a market there now? The "trains is other liveries" website had a photoshopped picture of a 153 at Blaenau Ffestiniog in Nightstar livery and one wonders what traffic from there to the other end of the route - perhaps Venlo - might have been ... but yet ...
