By Louise Scrivens
BBC News, London
Once a mere tool to help the mechanical sorting of mail, postcodes now deliver a powerful message.
NW1 is the current residence of actor Jude Law
A postcode could mean a difference of thousands of pounds to the price of a house and the social standing attached can, in some people's opinion, be priceless.
If your postcode is W1 you share it with Madonna, NW1 is the current hangout of actor Jude Law and controversial artist Tracey Emin has made E1 a trendy address.
Like the social cachet that comes with having a central London telephone number (020 7), a postcode can mean so much to so many.
But in an Essex town a group of residents would like the chance to have a London postcode.
Businessman Wilson Chowdhry lives and works in Ilford, which is also in the London Borough of Redbridge, has launched a campaign to change the current IG1 postcode to E19.
"The problem with having an IG1 postcode is it's not recognised as being a London postcode," he told BBC News.
Mr Chowdhry, who runs a security firm, said the Essex postcode is confusing customers as when they hear IG1 they presume the business is far away from London.
He said the area is surrounded by London postcodes such as E6 and E12 and that if Ilford had an east London (E) postcode it would help bring more business into the area.
The businessman told BBC News that he has a lot of support from businesses, residents and councillors in the area.
Britain first experimented with postcodes in Norwich in 1959
A 'postcode' letter can be sorted 20 times faster than one without
The Royal Mail postcode database contains more than 29 million addresses
SW1A 1AA is the postcode for Buckingham Palace
But Ilford estate agent Rafaqat Ali said a change of postcode would mean higher house and rental prices.
In E6, which is next door to Ilford, the difference in house prices compared with Ilford can be up to £15,000 and rental can be £100 a month higher, he added.
The code system currently used was introduced by Royal Mail between 1966 and 1974 to enable post to be mechanically sorted.
Cultural historian Joe Moran said it was the "pioneering gentrifiers" in the 1960s refurbishing run-down Georgian terraces who first saw the power of the postcode as a marker of social status.
"These people generally worked in the media and due to a lack of housing couldn't find homes in places like Chelsea so they started moving to areas such as Camden and Islington, thus changing the whole status of that area.
"London is different in that there are well established post codes, such a Wimbledon (SW19) associated with respectability, and there are edgy postcodes, such as W10 (north Kensington) which are desirable areas but very mixed and cosmopolitan.
"In more recent years the snob value of postcodes has increased."
In 2003, the residents of the Royal Borough of Windsor and Maidenhead launched a campaign to lose their SL postcode because it links them with nearby Slough - made famous by comedy series The Office.
Model, presenter and self-confessed Essex girl Jodie Marsh said she cannot understand why anyone in Essex would want to change their postcode.
"A lot of people I know in London are moving to Essex because there is more countryside and culture," she said.
"It's a really great place and I don't know why anybody would want to leave there or be ashamed of living there."
A Royal Mail spokesman said campaigners in Ilford had "virtually no hope" of changing their postcode.
"We only change postcodes for operational reasons, for example if a new estate is built and we need to change the sorting office but this is rare," he said.