There is a snobbery element that is unique to London.  The postcode sector that the property is in can have an effect on the property price.  People sometimes refer to where they live by the postcode as it can sometimes disguise where you actually live!  So for example if you live in Pimlico your postcode is SW1.  If you say you live in SW1 then people think immediately of the grand Buckingham Palace, Downing Street and Belgravia rather than the only slightly up-market Pimlico.

Here is the complete list of all the postcodes in London categorized by the good, the bad and the ugly!  This is really a hierarchy of postcodes relative to their neighbours.  It means that EC1 (Good) is better than EC3 (Ugly) but it does not mean that W4 (Good) is better than EC3 (Ugly) as they are not neighbours.

Good

E14Poplar, Isle of Dogs & Docklands
E18South Woodford
E3Bow
E4Chingford
E6East Ham & Beckton
E8Hackney
EC1Clerkenwell
EC2Moorgate
EC4Blackfriars
N1Islington
N10Muswell Hill
N13Palmers Green
N14Southgate
N15Tottenham (South)
N16Stoke Newington & Stamford Hill
N2East Finchley
N20Totteridge & Whetstone
N21Winchmore Hill
N3Finchley
N4Crouch End, Stroud Green & Finsbury Park
N5Highbury
N6Highgate
N7Holloway, Tufnell Park & Highbury
N8Hornsey
NW1Camden Town
NW11Golders Green
NW2Cricklewood
NW3Hampstead
NW4Hendon
NW5Kentish Town
NW6West Hampstead
NW8St Johns Wood
SE10Greenwich
SE12Lee & Grove Park
SE13Lewisham
SE21West Dulwich
SE22East Dulwich
SE23Forest Hill
SE24Herne Hill
SE3Blackheath
SW1Victoria
SW10West Brompton
SW11Battersea
SW13Barnes
SW15Putney
SW17Tooting
SW18Wandsworth
SW19Wimbledon
SW3Chelsea
SW4Clapham
SW5Earls Court
SW6Fulham
SW7South Kensington
W13West Ealing
W14West Kensington
W1Mayfair & Oxford St
W11Notting Hill & Holland Park
W4Chiswick
W5Ealing
W6Hammersmith
W8Kensington
W9Maida Vale

 Bad

E1Whitechapel & Stepney
E2Bethnal Green
E9Homerton
E12Manor Park
E13Plaistow
E16Silvertown & Canning Town
E17Walthamstow
N11New Southgate
N12North Finchley
N22Wood Green
NW7Mill Hill
NW9Hendon, Colindale & Kingsbury
SE1Southwark & Bermondsey
SE4Brockley
SE5Camberwell
SE6Catford
SE8Deptford
SE11Kennington
SE14New Cross
SE15Peckham
SE16Rotherhithe
SE17Walworth
SE18Woolwich
SE26Sydenham
SE27West Norwood
SW8South Lambeth
SW9Stockwell
SW12Balham
SW16Streatham
W12Shepherds Bush
W2Paddington
WC1Bloomsbury
WC2Covent Garden

 Ugly

E10Leyton
E11Leytonstone
E15Stratford
E5Clapton
E7Forest Gate
EC3Fenchurch
N17Tottenham
N18Edmonton & Upper Edmonton
N19Archway
N4Finsbury Park
N9Lower Edmonton
NW10Willesden
SE19Norwood
SE2Abbey Wood
SE20Anerley & Penge
SE24Herne Hill
SE25South Norwood
SE28Thamesmead
SE7Charlton
SE9Eltham
SW14Mortlake
SW2Brixton
SW20West Wimbledon
W10North Kensington
W14West Kensington
W3Acton
W7Hanwell