The fastest train currently operating in the UK is the Eurostar e320, which can reach a maximum speed of 200 mph (320 km/h) on the High Speed 1 line between London and the Channel Tunnel.
However, if we’re talking about trains operating on the UK’s domestic network, the title goes to:
Operational vs. Record Speed: The speeds above are what trains achieve in daily service. The absolute speed record for a train in the UK is held by the Eurostar Class 373, which hit 208 mph (334.7 km/h) during a test run in 2003.
Future Fastest: HS2 Trains: When the first phase of the new HS2 high-speed line opens (currently estimated between 2029-2033), the new trains will have an operational speed of 225 mph (360 km/h), making them by far the fastest in the UK.
The “Fastest” Brand: LNER’s “Flying Scotsman”: While its train (Azuma) has a 140 mph top speed, LNER’s London to Edinburgh