1:50k is typical resolution for road maps, if I was going off road and since they changed the trespass laws I would want enough detail to know that I am in the right when walking on someone elses land.
My walking experience is that for years increasing numbers of old footpaths have been blocked in the hope of removing public access and without accurate data then you are leaving yourself open. If you go armed with 1:5k OS Landline and the old bill turn up you can say this is the government data saying I am right and the land owner is wrong, now excuse me I have walking to do.
Biting the hand that feeds IT
