Tory mayoral candidate Zac Goldsmith was out on the campaign trail in Belsize Park this week, keen to outline why he believes the controversial Housing and Planning Bill will be a good thing for London in the long run.

Mr Goldsmith introduced a so-called “two-for-one” amendment to the bill, which will require two “affordable” homes to be built for every social home sold off under the proposed extension of the “right to buy” to housing association homes, but his Labour rival, Sadiq Khan, called this a “con” because replacement homes will cost up to £450,000.

But Mr Goldsmith defended his policy, claiming: “The £450,000 that Sadiq Khan is talking about relates to starter homes, which is a really valuable project which enables tens of thousands of people to get onto the housing ladder who otherwise would not be able to, but £450,000 is the cap, not the average.”

He said solving London’s housing problem should not come down to a simple, binary choice between social and market rate housing.

“You have to find a way to build for people across the income spectrum. Most people don’t qualify for social housing, but if you can’t buy a house, then you’re somewhere in the middle and you’re stuffed.”

Mr Goldsmith said he wants to see 50,000 new homes per year built in London by 2020, but hasn’t said what percentage of those homes should be defined as “affordable”.

He said: “I just don’t believe in those targets, set by politicians who don’t want to have to explain how they are going to deliver. It’s a lazy way out of having to explain a policy, and I think that with housing, they never get met.”

He says he sympathises with those who feel trapped in the expensive, private rented sector, but is critical of Mr Khan’s proposals for a “London living rent” scheme.

He said: “I don’t think rent controls work. The first thing it does is suppress the amount of homes that are built. Rent controls could only happen if the government agreed to it, and they won’t. Sadiq Khan is offering an academic argument, which is completely dishonest.”

Mr Goldsmith also blasted Mr Khan’s pledge to freeze transport fares for Londoners as “completely bonkers. A crazy, uncosted experiment which would have a massive impact on London.”

He said: “It will take two billion out of the TFL budget, which is a recipe for disaster. All of the projects for TFL improvements are crucial to keep London moving. If he is going to take two billion out of the budget, what’s he going to cut?”