Caroline Pidgeon has been a politician for 18 years: first as a councillor, from 1998 until 2010, then from 2008 as a London assembly member. Now, the 43-year old is running for mayor, and is first on the Liberal Democrat’s assembly list.

Like Siân Berry, the Green party candidate, if elected Pidgeon plans to renew the London 2012 Olympic Games precept for housebuilding. Londoners currently pay £20 a year towards the Olympics. It’s a precept on council tax that runs out next year, but Pidgeon would ask residents to continue to pay it and use the revenue to fund building.

“What I specifically want to do is build 50,000 – what I’m calling – council homes. Homes that are at council rent-type levels and genuinely affordable,” she says. “In addition to that, because we need more of all tenure, we’d look over that four-year term to also build a further 150,000 homes for private rent, private sale, intermediary and rent-to-buy. So we’d have a range to try to meet the wider housing need in London.”

Leaving housebuilding to private developers and the market is a mistake, Pidgeon says, as a lack of supply forces up prices and benefits developers. “It feels to us that we just aren’t building enough homes, and private developers only build as many as they want. Actually, they don’t want the market flooded because it affects their bottom line,” says Pidgeon. She wants to set up a housing company run by the mayor through the Greater London Authority (GLA), which would build houses for Londoners, and set up a construction academy.

With budgets being cut around the country funding something like that might be a tricky issue, but Pidgeon has a few ideas on how to get around austerity. “Skills funding is possibly being devolved to London and possibly the further education colleges as well, so we’d look at that,” she says. “I’d look at whether there’s some European funds we can link in to bid for, so I think there are lots of creative ways to fund it.”

She also has some ideas for the private rented sector. Some London boroughs have implemented selective licensing – whereby landlords of certain properties have to apply for licenses through the local authority in order to rent them out – and Pidgeon wants to roll that out across the city. She also wants to see a London-wide landlord registration scheme to give a kitemark for homes, and a letting agency run through City Hall for newly built private-rented homes.

This government is trying to kill off social housing as we know it Caroline Pidgeon

“An awful lot of people out there who rent homes do it properly, but there’s a minority who aren’t, and that’s who we need to be tackling,” she says. “We want renters to have the strong hand rather than it always being the landlord.”

Pidgeon also believes that increased housebuilding will result in lower rents.

Street homelessness, meanwhile, is rising in the capital, and Pidgeon feels housing affordability exacerbates the problem. “I recently went to a hostel in east London and chatted to a number of residents,” she says. “They’d all become homeless for very different reasons. One had alcohol issues, another came from care, one had a four-bedroom home with her family but mental health issues had spiralled and she’d lost her home. They were all petrified at what would happen once they left [the hostel]. You’ve got to be doing something to help people in society, and that’s why we’ve got to be building council homes.”

Despite the Liberal Democrats having been in coalition with the Conservatives until the general election last year, she is critical of the Tories’ record on housing. Pidgeon is particularly critical of policies such as the forced sale of high value council houses and the recent right-to-buy changes for social landlords. “This government and previous governments have been very weak on housing, and I do think they are trying to kill off social housing as we know it. The right to buy for housing associations is just wrong. Right to buy is just stripping out decent housing,” she says.

When asked what the current Liberal Democrat position on the bedroom tax is, she consults her campaign manager, who confirms that the party now oppose it, while under Nick Clegg they backed it.

Every mayoral candidate agrees that London needs more homes – but where would they go? Pidgeon says under her leadership some would be on GLA-owned and other public sector land, and that she would work with TfL to make creative developments. The planning categories available to local authorities could be changed to push affordable housing too, she argues. “I think it’s really important we say where we want affordable housing and be able to give that clear steer to developers. I don’t mean starter homes, by affordable housing, which looks like it will eat up every element of social rented accommodation.”

Developers often complain that planning regulations hamper building – but Pidgeon doesn’t buy it, nor does she feel relaxing planning regulations would boost completion rates. “Developers would like there to be no rules whatsoever so they could do what they’d like: you’d end up with bad design, and still wouldn’t have the volume you need,” she says. “I’d look to be very strong mayor, really working hard with developers, with the sector, to really build the homes we need.”

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