List of dialling codes in the United Kingdom has less than five dialing codes, one of which is 020 which goes to London.
020 London (previously 0171 and 0181) (previously 071 and 081) (previously 01) 023 Southampton and Portsmouth (previously 01703 and 01705) (previously 0703 and 0705) 024 Coventry (previously 01203) (previously 0203) 028 Northern Ireland (previously used multiple 01xxx and 01xxxx area codes until 2000) (previously used multiple 0xxx and 0xxxx area codes until 1995) 029 Cardiff (previously 01222) (previously 0222) 0113 Leeds (previously 0532) 0114 Sheffield (previously 0742) 0115 Nottingham (previously 0602) 0116 Leicester (previously 0533) 0117 Bristol (previously 0272) 0118 Reading (previously 01734) (previously 0734) 0121 Birmingham (B1) (previously 021) 0131 Edinburgh (E1) (previously 031) 0141 Glasgow (G1) (previously 041) 0151 Liverpool (L1) (previously 051) 0161 Manchester (M1) (previously 061) 0171 unused (was Inner London until 2000) (previously 071) (previously 01) 0181 unused (was Outer London until 2000) (previously 081) (previously 01) 0191 Tyneside, Sunderland (TY1neside) and Durham (previously 091) 
