Liberal Democrat councillors from SE1 failed in their bid this week to get higher taxes on UK homes bought by foreign investors adopted as party policy.
Southwark Liberal Democrats put forward a proposal at their party's conference in Glasgow calling for overseas buyers to be charged a higher rate of stamp duty if the property is not their primary home.
"Every year Southwark Liberal Democrats come to conference to call on the Government to build more housing," Cllr Anood Al-Samerai told delegates.
"Every week I meet hard-working, good people in my advice surgeries who are desperate to find somewhere they can afford to live.
"Every day our Labour council in Southwark breaks my heart by rolling over to developers and not getting enough affordable homes in our communities.
"And yet ... there is another devastating problem happening in London, the south east and other major cities in the UK.
"This is a devastating trend where homes are no longer being built as homes but as investments for businesses and individuals from abroad, as safe places to put their money.
"Last year, 60 per cent of new build properties in inner London were marketed and sold abroad off-plan."
She blamed the homes-as-investments phenomenon for pushing up house prices out of reach of local people.
Only this weekend, homes in the new One Blackfriars skyscraper next to Blackfriars Bridge went on sale in Hong Kong.
Cllr Al-Samerai continued: "It also destroys communities having homes sitting empty. There's a block in my ward which has two shared-ownership flats ... the other 14 flats ... sit empty most of the time.
"One of them is owned by an Arabian prince for his driver to stay in once or twice a month.
"That's not community. Homes should be for people to live in, work in, bring up their families, contribute to the community and know their neighbours."
She insisted the measure was not xenophobic: "It's not anti-foreigner; it's pro homes."
Cllr Al-Samerai added: "I am someone who was welcomed to London – our great global and diverse city – when my family had to leave Kuwait as a result of the first Gulf war.
"I know that London is a great home for people from all over the world. But that's exactly what it should be – a home, not a safe place to put your money."
Defending her proposal against charges of illiberalism, she said: "It is liberal to support community; to allow people to get on in life".
Later in the debate South Bermondsey councillor Graham Neale explained that the extra stamp duty could allow extra spending on local projects.
"The minor changes we are requesting will allow our government to prevent these buyers from using our homes and our communities simply as a cash cow," he said.
"The use of this measure will ensure local communities will benefit directly from inward investment, making sure speculators contribute to the amenity of the communities into which they are buying."
Cllr Neale said that Southwark residents' support for the campaign by Simon Hughes MP and local Lib Dems on this issue had been "overwhelming".
A vote on the proposal by Southwark Lib Dems was lost by a narrow margin after Danny Alexander, chief secretary to the Treasury, urged delegates to reject the measure.
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