Politicians and charities have called for the removal of metal spikes put in place outside a block of flats to prevent homeless people from sleeping there, after an outcry on social media.
London mayor Boris Johnson called the two-inch spikes at 118 Southwark Bridge Road "ugly, self-defeating and stupid" after pictures of them were shared widely on Twitter, while housing minister Kris Hopkins said their installation was "deplorable".
Almost 7,000 people have signed a petition calling for the removal of the "inhumane" spikes outside the central London location, where one-bedroom flats are currently being offered for £500,000.
Homeless Link, which represents homelessness charities, also condemned the spikes.
Jacqui McCluskey, its director of policy and communications, said: "It's shocking to see the use of metal spikes to discourage rough sleeping and hardly helps deal with the rising number of people who are forced to sleep on our streets.
"Many people who sleep rough just don't know where to turn and are amongst the most vulnerable in our society. Sleeping on the streets is dangerous, bad for your health and individuals need support.
"This approach is not only inhumane, it does nothing to tackle the causes of rough sleeping and just moves the issue on for someone else to deal with."
The building where the spikes are located is partly occupied by the British School of Osteopathy, but the spikes are next to an entrance to adjoining flats "which we may not use and have no right to manage or control", a BSO spokeswoman said.
The BSO said the developer of the flats was Residential Partners Ltd. It has yet to comment.
Boris Johnson weighed into the debate this morning.
Tweeting from his @MayorofLondon Twitter account, Mr Johnson also defended his record on tackling homelessness.
He tweeted: "Spikes outside Southwark housing development to deter rough sleeping are ugly, self defeating & stupid. Developer should remove them ASAP.
"We've spent £34 million on the likes of 'no 2nd night out, reaching 3/4s of rough sleepers, but must do more. Spikes are simply not the answer."(sic)
Tory housing minister Kris Hopkins added: "The actions of this developer are deplorable and deeply unpleasant, and I want to see them remove these 'spikes' as soon as possible - I don't know what self-respecting architect would want to be associated with such an offensive measure."
Southwark Council said it could look into any health and safety or planning concerns reported to it.
Councillor Peter John, the council leader, said: "Anyone who is sleeping rough deserves to be treated with compassion and respect - not spikes. This is why the council has a dedicated officer working with a number of homeless charities in the borough to find them shelter and the right support.
"Southwark Council is not involved with the installation of the spikes outside of the property at 118 Southwark Bridge Road and we do not feel this is the best way to deal with the problem.
"The spikes were not part of the original planning application for the building but would be considered too small to come under planning regulations, however we will continue to see if there is anything within the council's power to get these measures removed or an alternative solution found."
Local Labour politicians attacked Mr Johnson's record on homelessness.
Tom Copley, its housing spokesman on the London Assembly, said: "That anyone at all should be sleeping rough in one of the richest cities in the world is bad enough, but using metal spikes to deter rough sleepers is cruel and inhumane.
"Having promised to end rough sleeping by the end of 2012, Boris Johnson has in fact presided over a doubling of the number of people who sleep rough since he took office."
Protesters are also planning a demonstration outside a branch of Tesco where it says similar spikes have been installed.
Left Unity said it had called Thursday's hour-long protest outside the "Metro" in Regent Street.
Tesco said the spikes outside the store were not installed to deter rough-sleepers. A spokesman said: "The studs were put in place to try and stop people engaging in anti-social behaviour like smoking or drinking outside our store, which can be intimidating for our customers."