Lord0 wrote:

I got new carpets fitted. As a result I need to shorten two internal
doors by *about* 1cm.

If you don't want to remove then rehang the door, one of these can do a
good job:

http://www.screwfix.com/app/sfd/cat/...33430&ts=02691

The saw is easy to use and gives a fine smooth finish, no need to plane
afterwards. It's very easy to use and provided you draw a pencil line
along the door to cut along it's easy to cut a straight line.