Where in the UK is area code 0151 336?

UK telephone area code 0151 (or +44 151 in international format) is Liverpool and surrounding areas. A telephone number beginning with 0151 3368 is most likely a BT landline in Neston, Wirral; however, with number portability, any specific 0151 number may be located anywhere in the greater Liverpool 0151 area, served by any local telephone company.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)