The Liberal Democrats mayor of London candidate will create a central housing company to take control of building homes in the city, if she is elected.
Luisa Porritt set out her election policies when she launched her campaign from a Camden pub at 11:00 GMT.
She used her speech to call on Met Police Commissioner Dame Cressida Dick to resign over the force's handling of a vigil for Sarah Everard.
The election for mayor of London will take place on 6 May.
LONDON'S ELECTION: THE BASICS
What's happening: On 6 May people will vote to elect a mayor as well as 25 members of the London Assembly. Together, they make up the Greater London Authority (GLA), which governs the capital - you can register to vote here.
What difference does it make? The mayor has a £19bn budget and is responsible for Transport for London, the Metropolitan Police, and has a role in housing, planning and the environment. The London Assembly holds the mayor to account by examining their policies. Find out more here.
Who is standing? London's current mayor, Labour's Sadiq Khan, is seeking re-election and his main challenger is Conservative Shaun Bailey, but there are 18 others running.
At the launch of her "take London forward" campaign, Ms Porritt said jobs, homes and clean air are "three basic needs" and she would work to "give Londoners what they need, so that every person can thrive in our recovery beyond the pandemic".
A London housing company would allow City Hall to "take control of building the homes we need directly", the Lib Dem candidate said.
Ms Porritt also announced that she would commission a study looking at converting offices into homes, as "in the coming years, we'll have more empty office space come on to the market than ever before".
During her speech, she also urged Dame Cressida to resign over the Clapham Common vigil, as "from start to finish, the Metropolitan Police got it horribly wrong". Lib Dem leader Sir Ed Davey made the same call in the aftermath of Saturday's events.
Dame Cressida has said she is not considering her position following the vigil, where officers handcuffed women and forcibly removed them from crowds.
You can find a list of all the candidates who have said they will be running for London's mayor here.