It's certainly possible to pay for your own rating at one of the two non-NATS training establishments and get a job afterwards - with a tower rating you should be able to land a job at a smaller regional airfield. You might be lucky and get a job at one of the larger ones, like Liverpool, East Mids or Newcastle, although generally speaking they are more likely to be in the position to take only fully-rated and experienced ATCOs, if they so choose.
As for getting a job at an airport where NATS provide ATC, that is extremely unlikely. These airports are (in the UK):
Aberdeen; Glasgow; Edinburgh; Belfast Aldergrove; Manchester; Birmingham; Luton; Stansted; Cardiff; Bristol; Farnborough; Heathrow; London City; Gatwick; Southampton.
NATS, when they do recruit externally (and it's not that often), take on only fully-rated and experienced controllers. If you want to get into NATS without passing their ab-intio selection process and training programme, then you will need to have both tower and approach radar ratings as well as a few years experience under your belt, ideally at one of the bigger non-NATS airports. Sorry if that sounds negative, but that's the way it is. On a positive note, it can be, and has been, done.
Your best option by far, though, is passing the NATS ab-initio selection. Good luck with that!
Last edited by rodan; 21st February 2009 at 02:01.