Multimillion pound housing developments in London are segregating less well-off tenants from wealthy homebuyers by forcing them to use separate entrances.

A Guardian investigation has discovered a growing trend in the capital's upmarket apartment blocks – which are required to include affordable homes in order to win planning permission – for the poorer residents to be forced to use alternative access, a phenomenon being dubbed "poor doors". Even bicycle storage spaces, rubbish disposal facilities and postal deliveries are being separated.

The Green party accused developers of showing "contempt for ordinary people" by enforcing such two-tier policies.

Bill De Blasio, the mayor of New York, has said he will take action to prevent new developments being built with separate entrances. Photograph: Marco Cantile/Demotix/Corbis

This week New York's mayor, Bill De Blasio, said he planned to take action to prevent new developments being built with separate entrances and facilities for low-income residents. His pledge followed a furore over a luxury block on the city's swanky Upper West Side which will have what US newspapers have dubbed a "poor door" for the social housing units on the site. But while the approval for segregated entrances in just one building in New York generated headlines, they are fast becoming standard practice in London.

"When Ken Livingstone left office he was keen that all developments should have their social housing 'pepperpotted' – mixed in with all the other more upmarket accommodation," said Ed Mead, a director at estate agent Douglas & Gordon which sells upmarket properties in central London. "This didn't go down well with developers with the result that most developments now have a separate entrance and a different look."

Tracey Kellett, a buying agent who trawls the capital looking for homes for wealthy clients, said a number of developments have separate entrances "so the two social strata don't have to meet". In one: "The affordable [housing] has vile coloured plastic panels on the outside rather than blingy glass."

At one building bordering the City financial district, the Guardian discovered wealthy owners accessed their homes via a hotel-style lobby area, while social housing tenants enter through a side door in an adjacent alley alongside trade entrances.

How One Commercial Street is marketed to wealthy City workers.

In marketing information for another development currently under construction, would-be residents have been promised that the affordable homes will have a separate entrance, no access to car or cycle parking and that post and bins will also be divided.

As the London housing market has boomed the expectations of some of the capital's wealthiest homebuyers have grown and many properties now have communal areas akin to those in some of the world's best hotels.

Service charges to maintain these are high, and a separate entrance means housing associations and their tenants do not face these extra costs. However, as in New York, there are concerns that it is leading to increasingly divided communities.

Green party London assembly member Darren Johnson said: "This trend shows contempt for ordinary people, and is about developers selling luxury flats to rich investors who don't want to mix with local people."

He added: "The mayor and councils have been turning a blind eye to this for too long, they should simply refuse applications that have separate facilities or that refuse any affordable housing on this basis."

A spokesman for de Blasio's office in New York said this week : "We fundamentally disagree with (separate doors), and we are in the process of changing it to reflect our values and priorities. We want to make sure future affordable housing projects treat all families equitably."

Developers said separate doors let housing associations keep costs down as they avoided premium service charges paid by private residents.

Peter Allen, sales and marketing director for Londonewcastle which is behind the Queens Park Place development in north London said housing associations were sometimes unable to pay for all of the facilities covered by service charges. "The simplest way from a design perspective is to have things separate."

Side-entrance shame

The brochure for the upmarket apartments of One Commercial Street, on the edge of the City, boasts of a "bespoke entrance lobby ... With the ambience of a stylish hotel reception area, it creates a stylish yet secure transition space between your home and the City streets".

In common with many of London's new concrete and glass residential blocks there's a concierge, on hand 24/7 to service the every need of residents paying a minimum of £500,000 – which only buys a studio flat – to live in this booming part of the city.

But the lobby is out of bounds to some of those who live in the building. What the brochure doesn't mention is a second door, with a considerably less glamorous lobby, tucked away in an alley to the side of the building, alongside the trade entrance for Pret a Manger. This is the entrance for One Commercial Street's affordable housing tenants.

Curzon Street, where developers argued affordable housing provision would result in 'design inefficiencies'. Photograph: Graham Turner for the Guardian

In a bid to ease the housing crisis, developers are obliged to provide a set proportion of affordable homes when they draw up a new project, but they are often able to negotiate this figure down with local planners. Some provide the cheaper homes in separate blocks, but in a single structure development the affordable homes are often on separate floors – with separate entrances, lifts, car parks and even rubbish bins, so that upmarket apartment buyers have no contact with those occupying the social housing in their buildings.

In some cases, developers have even used the fact they need to provide separate doors and lifts to argue against putting affordable homes on the same site as their premium apartments. Planning documents for the 56 Curzon Street development in Mayfair show that the developers told the local council "that on-site provision of affordable housing would result in significant design inefficiencies due to the need for separate entrances and building cores".

Some are coy about the subject. Native Land, which is currently building Cheyne Terrace just off Kings Road in Chelsea, complete with a swimming pool and gym, refused to comment when asked if its 13 affordable housing units would be accessed via a separate door. However, the website of John Robertson Architects, which has designed the building, makes it clear this is the case.

In north-west London the developers behind Queen's Park Place are more upfront about how its 28 affordable and 116 market-rate homes will co-exist – its marketing website says the external appearance will be uniform across all properties – or "tenure blind". But inside the building the two types of resident will be treated very differently: "Affordable tenants will not have use of the main private residential entrance, private courtyard gardens or basement car and cycle parking. Services including postal delivery and refuse storage are also divided."

This does not just happen where there are large numbers of affordable homes on a site. In Chiswick, The Corner Haus development which is to be completed this summer, has just two affordable units, but these are also expected to have a separate entrance.

Of course, the separate doors to these developments mean that the housing associations who run the affordable properties and their tenants do not face the service charges attached with the luxurious surroundings that wealthy buyers have now come to expect and accept. However, the stark difference between the entrances, and, in some cases their positioning, rankles with some of those who live there.

Through the main door of One Commercial Street the lights shine brightly in the hotel-style lobby. There is luxury marble tiling and plush sofas, and a sign on the door alerts residents to the fact that the concierge is available. Round the back, the entrance to the affordable homes is a cream corridor, decorated only with grey mail boxes and a poster warning tenants that they are on CCTV and will be prosecuted if they cause any damage.

Brooke Terrelonga lives here with her nine-month-old son – they moved into a social rented flat four months ago and she was surprised to find that she wasn't allowed to use the front entrance. Her mother, who doesn't want to be named, said she felt unhappy about her daughter returning home at night to the poorly-lit alleyway. She motioned towards two lights on the wall, either side of the door, which were the only lightling in sight. She said: "It's like the cream is at the front and they've sent the rubbish to the back."

Another tenant, Judy Brown, had also expected to be able to get to her flat through the main entrance. "I call it the posh door. I feel a little bit insulted. It's segregation." Brown said that the lifts kept breaking down and she often had to take the stairs to her ninth-floor flat. "When both the lifts weren't working they did say that if you were pregnant, had a health problem or a baby in a buggy you could use the main entrance," she said. Otherwise, the tenants said, they were "locked out" of the main lobby.

James Moody, managing director of Redrow London, which built One Commercial Street said in a statement that his firm was committed to providing homes "at all financial levels" and that 34% of the total accommodation in the building was affordable.

"As One Commercial Street is located on the edge of the City, we have built a product that appeals to this market of young professionals and families who want to live close to their place of work and enjoy the benefits of a full concierge service and hotel style lobby, which they pay a premium for through their service charge.

"Affordable accommodation is managed separately by Network Housing who have full control of the services and facilities provided to its tenants and have a set cap for service charges.

"In addition, we have taken every step necessary to ensure that our development meets the needs of all of its residents and we go through a lengthy consultation process with housing associations to establish both a design that meets their requirements whilst making it as affordable as possible for their residents."