Can I travel with Eurail in Great Britain / United Kingdom / England?
No, there are no Eurail passes available for England, Wales, Scotland and Northern Ireland. The only part of the British isles where you can travel with Eurail is the Republic of Ireland, with its capital Dublin (Republic of Ireland: railway info / tourist info).
If you have a Eurail Global Pass, or a Eurail Select Pass or Regional Pass which is valid in the Benelux, you may profit from reduced boat crossings and Eurostar trains to Great Britain and London.