To quote David Else in Lonely Planet's 'Walking in Britain', deciding what to take is tricky. You can choose between the Ordnance Survey Landranger 1:50,000 maps, or for more detail (which is recommended) the Explorer 1:25,000 series. Either way, there are a lot of maps to carry.
The alternative is to use the Strip Maps shown on this page. In theory, using these should suffice, but in practice navigating is difficult, especially in bad weather, because these maps only show a limited part of the area you're passing through. If you wander off the route, you may stray from the map as well, and then you're lost!
We recommend using a combination of the strip maps plus either Landranger or Explorer maps of the the Lake District, where the possibility of bad weather and the complicated route means you really need more coverage
There are two sets of strip maps that we recommend, but unfortunately only one we can sell.
Ordnance Survey produced two strip maps in 1999 on a scale of 1:27777. These maps, printed on both sides, show the route in narrow strips, together with extracts from Wainwright's original guide. These have been a bestseller since they were introduced, but for some reason best known to Ordnance Survey, they have discontinued publication. Unfortunately we have now depleted our remaining stock.
With Ordnance Survey having decided to discontinue their strip maps, Harvey have stepped into the breach with two maps of their own. These are on a smaller scale of 1:40000, but this does mean that they are printed on one side only, and are easier to use when that wind is really whipping across the moors! Obviously they lack Wainwright's way with words, but you can always buy Wainwright's book in compensation.
Harvey reprinted both maps on polethylene in 2008. They are clear and easy to read, and give useful information on facilties, services and alternative routes. These are an excellent replacement for the discontinued OS maps.