PS: as you're clearly dealing with UK phone numbers, here's an interesting piece of trivia...

Brighton's STD code is 01273. Back in 1995 nearly all the STD codes in the UK were changed with the insertion of that "1" (e.g. London changed from 071/081 to 0171/0181). So before 1995, Brighton's STD code was 0273.

Notice what letters 2 and 7 represent on a mobile phone keypad? 27 = BR. Apart from a few larger cities that have been renumbered, nearly all STD codes in the UK have a similar heritage. 01323 is Eastbourne; 32=EA. 01444 is Haywards Heath; 44=HH. 01424 is Hastings; 42=HA. They're all derived from telephone exchange names from back before STD was introduced.