There are different tickets that allow you to travel on most services. You can't have 100% unrestricted travel as there are always certain services that can't be accessed by certain tickets; for example, special services such as Eurostar and small private rail companies operate differently. There are also likely to be restrictions on time of day unless you get a very expensice ticket. But, if you are planning a lot of rail travel around the UK and don't mind being a bit flexible over timing, there are some good deals around.

You may like to take a look at the All Lines Rover Ticket. This gives you a week's travel for £375 (though fares can go up of course) or two weeks for £565. The price comes down if you are a student or retired.

Another good option is the Britrail Pass, which is more flexible - you can get one for just a couple of days or a much longer period. Prices and details can be found on the right of the page.