Britain is fortunate in being covered by the superb Ordnance Survey maps in scales of 1:50,000 and 1:25,000 - these are available on paper or laminated in plastic, the latter being much harder wearing. In addition, Harvey and the BMC both publish excellent maps to the more popular UK mountain areas at 1:40,000 and 1:25,000 respectively - these are printed on polythene or waterproof paper and so are very durable.
For planning trips and general map work 1:50,000 is a useful scale as a large area can be taken in at a glance. 1:25,000 is a scale that shows every fence and wall line and gives considerably more detail so is more useful where precise navigation is required. And 1:40,000 is a good compromise between the two.
We stock maps of the more pointy and wild places in the UK that are likely to be of interest to the climber or hill walker, but can usually obtain quickly any we do not have in stock.