Jake D wrote:
I'm not sure of the situation regarding canoes, rivers, and permits in
the UK, but I have heard of people doing river runs in canoes. Which
are the most scenic and natural rivers in the UK, suitable for long
canoe trips (if any)?

The Scottish 'classics' are the Tay, Tweed, Dee and Spey. They all have
their charms, the The Spey is probably my favourite. For a small enough
group, wild camping is possible on most stretches of these rivers
making them ideal for multi day descents, or ascents if you're that way
inclined.

There is a rather fine publication entitled 'Scottish Canoe Touring'
which provides a guide to most of the water in Scotland suitable for
touring. It's available mail order from the SCA:

http://www.canoescotland.com/