Well this months BBC Wildlife features an article on rehabing wildlife. Apparently
under the Wildlife and Countryside Act it is an offense to release rehabilitated animals on the schedule 9 list (such as Grey Squirrels) back into the wild without a licence.
As very few licences were issued for the purposes of rehabilitation, the RSPCA ended up putting down every Grey Squirrel brought into them regardless of the the animal's condition, to comply with the law.
Now though, Natural England* will grant licences in certain circumstances, allowing the release of some non-native species. This will make a huge difference to the rehabilitation of some grey squirrels and muntjacs. Rehabbed greys can now be released in "acceptable" areas (i.e. where there are no Red Squirrels).
* yes I know Aberdeen is in Scotland
Text lifted from the excellent BBC Wildlife magazine go buy it. The above view seems quite sensible I understand why you can't release a Grey Squirrel in say Cumbria but it makes no sense not to release it in say Essex. This of course also raises the question of what is "non-native". Rabbits were introduced so are they non-native or was there release sufficiently long ago.
I do think the Grey Squirrel gets a bad press, yes I know it has caused great damage to the native Red but it is hardly its fault that some idiot released them. Nowadays they are so widespread we will not be able to remove them so we have to be smart to protect the Red.
While mentioning BBC Wildlife I should say they are promoting a new magazine BBC Countryfile looks like it will have a similar mix to the TV program it is spun off from so may be worth a look.