Stripymouse - you can actually find a bedsharing policy on the site www.babyfriendly.org.uk
You should not bedshare if you are under the influence of drink or drugs ( including partner in bed). There are other reasons such as being a smoker etc.
I personally was not concerned about sleeping with my babies - I had seen a few programmes that showed how parents actually moved about in their sleep to accommodate a baby in bed.
The hospital has a concern that babies may fall out and parents mught sue. At our hospital mothers are not dissuaded from having their babies in bed with them and cot sides are provided for that purpose.
There is a difference made between bedsharing and co-sleeping though.
You do what you are comfortable with. For me, it was a way of sleeping but you are always on the alert to some extent.