The Nightstar was a proposed overnight sleeper train service from various parts of the United Kingdom to destinations in mainland Europe, via the Channel Tunnel. To run alongside the Eurostar, and north of London day-time Regional Eurostar services which were never operational, the Nightstar was the last part in a proposed round-the-clock passenger train utilisation of the Channel Tunnel. The Nightstar service was to have been operated by European Night Services, a company mostly owned by European Passenger Services (the then-named operator of the Eurostar service).