RoamTheWorldCellPhones.com

Cellphone GSM Frequencies: 900/1800

(This means you will need a GSM cellphone that will work on 900MHz or 1800Mhz to use it in the United Kingdom.)

Cellular carriers for the UK

Mapesbury Communications Limited (MCom) (UK01)

Frequency: GSM 1800
Website: www.uk01.com

Coverage Map

Orange PCS Ltd

Frequency: GSM 1800
Website: www.orange.co.uk

Coverage Map

T-Mobile (UK) Limited

Frequency: GSM 1800
Website: www.t-mobile.co.uk

Coverage Map

Telefónica O2 UK Limited

Frequency: GSM 900/1800
Website: www.o2.co.uk

Coverage Map

VODAFONE Ltd

Frequency: GSM 900/1800
Website: www.vodafone.co.uk

Coverage Map

If you've used either of these networks or roamed in the United Kingdom, please post about your experience and the cost. Feel free to ask questions.