Zac Goldsmith is the Conservative MP for Richmond Park and the Party’s candidate for Mayor of London.

There are just forty days to go to secure London’s future, and I’m giving this race everything I’ve got.

One thing we know for certain is that the result will be close. London is like a giant marginal constituency. At the last mayoral election Boris beat Ken by just over 62,500 votes, out of an electorate of 5.8 million.

It would take just over 31,000 people – less than 1000 in each borough – to switch their vote from Conservative to Labour for Corbyn’s man in London to take the keys to City Hall.

So I’m out campaigning today with Conservative activists and Londoners, fighting for every single one of those votes.

Meanwhile Khan, Corbyn and the Labour machine are massing in their Islington stronghold, doing everything in their power to return London to Labour rule.

In May there are important elections across the country, but the battle in London is absolutely vital. The next London Mayor will be in charge of a £600 billion economy, a 32,000 strong police force, and a transport system that handles 24 million journeys every single day.

The opportunities to extend Boris’ success and do something good for London are huge.

I’ll increase the green spaces in London, rather than threaten the green belt with development. I’ll deal with the housing crisis by building homes for all sections of society, rather than setting bogus targets.

I’ll stand up for London, rather than experiment with our City’s future.

The alternative looks very different. Khan experimented with Corbyn and wrecked the Labour Party, it’s our job to stop him doing the same to London.

Take his flagship policy, an unfunded fare freeze that Transport for London have confirmed would blow a £1.9 billion hole in the transport budget. It would mean scrapping vital upgrades at a time when our transport system is under huge pressure.

And because it’s only by growing the network that we can unlock new brownfield sites for development, it would make the housing crisis worse. Without that investment, Khan will either fail to deliver the homes we need, or build on our precious Green Belt.

All in all, Khan has made £5 billion in unfunded spending commitments, which we know would have to be paid for somehow. Just last week he refused to rule out raising council tax.

We all know how this story ends. Under Ken Livingstone council tax rose by 152 percent. We could expect the same under Khan.

So there is a very clear choice at this election. You can choose to protect Boris’ success or see it dismantled.

You can choose to protect and expand our precious green space, or you can choose to build on it.

You can choose to invest in the transport network we all rely on or choose a £1.9 billion black hole that will stall our transport network.

I will build on Boris’s legacy, and make it work for Londoners by fixing the housing crisis, growing the transport network, cleaning up our environment, and making our streets safer. That’s my Action Plan for Greater London: all paid for without increasing mayoral council tax.

I am the only candidate who can work constructively with this Government to secure the funds and powers to deliver that plan.

We are the most Googled and visited city on earth: the whole world is watching London, so don’t leave it to chance. Back me on May 5th and let’s build that greater London.

Boris Johnson and Zac Goldsmith Campaigning in Sidcup