Two weeks from now, Labour will have a new leader. Yet his – and it's usually always "his" – biggest electoral test before winning a general election will be winning London in 2012, and using that as a springboard to beat this Tory government – a government that is shameless about hitting the poorest hardest.

Labour members and trade unionists have to decide who can best beat Boris Johnson – Ken Livingstone or myself? Who can best win back the voters Labour lost in outer London, in parliamentary seats like Enfield North and Brent Central? Equally important, it's about who best represents the future for the Labour party, and who can inspire a new generation of Labour party members to join our movement.

Most Labour party members probably share my view that Ken is a great Labour party figure, and we owe him a debt of gratitude. I first became a fan at the age of 14, when Ken led the GLC. Ken has been at the forefront of London politics for over three decades, but sometimes the status quo must change.

So what change do I offer? For a start I'll revolutionise the way City Hall is run. I'll sweep out the habit of London mayors appointing their mates to top jobs. Of course we need political appointees, but the corrosive perception of cronyism that's blighted the mayoralty since its inception must be tackled. All mayoral appointments should be vetted by a tough new appointments panel, so jobs don't just go to who you know.

We also need to take the game to Boris Johnson. Boris won in 2008 because he focused relentlessly on outer London voters, and on the number one issue for the capital's citizens – crime. Yet, since then, his mayoralty has been dominated by inaction. We have blue paint and new bikes – although none for outer London. But Boris Johnson has failed to make any progress in dealing with knife, gun and gang crime.

Tragically, 14 teenagers have died on the streets so far this year; the rate of fatalities has matched that seen in 2008, when Boris was first elected. Earlier this year, one teenager was killed three streets from where I live in Mile End, and where I'm bringing up two young children. We have to force police to prioritise the issue, and I'll do that by taking control of the Metropolitan Police Authority, doing the job that Boris can't be bothered to do. We have to fund more youth workers who actually work on the streets. We need resources directed at better enforcement – such as the knife arches I saw this week in Streatham – but if we want to solve the problem, we need to fund preventive work and tackle disadvantage.

Fundamentally, we have to make London fairer. Levels of inequality in London are nothing short of scandalous. I say that as someone who lives near Canary Wharf's gleaming spires, but who spoke recently to a young neighbour who only trades heroin and crack cocaine. He knows he won't be moving on to a trading floor, only a prison block. But the London-wide paid work experience programme that I'll introduce will allow kids from Ealing to Eltham to experience work in an investment bank, TV station or law practice – regardless of who their parents know.

There's a clear need to get people on the housing ladder. You have to be very rich or very poor to live in inner London. Coalition attacks on housing benefit will only make things worse. Ordinary Londoners on salaries of less than £30,000 need to be able to get mortgages on reasonable terms; setting up a "mayor's mortgage" that uses the balance sheet of the Greater London authority to help people borrow modestly will help people buy homes they could not otherwise afford.

Mayoral job applicants are also – it seems – required to introduce an emblematic bus. Mine won't be a bendy bus or a Routemaster. Frankly, it's not what a bus looks like that matters, it's what it does. My focus will be school buses, and I'll develop the existing poorly used network. School buses will help parents get kids to school on time – especially in outer London – while reducing the 20% of London's congestion caused by the school run. And I'll slash bus fares that have been hiked again and again (12.7% this year alone) by reintroducing the western extension zone that covers Kensington and Chelsea.

I used to work in an office that had "Change or Die" over the door. I've always had some sympathy for that outlook, but I felt it especially strongly after speaking during this mayoral campaign to a 19-year-old from Haringey who was stabbed and shot six times. He's now working with a project to stop other gang members getting sucked into crime. He knew he had to change or die.

The Labour party should take a leaf out of his book – because Labour has no divine right to exist. We must fight to secure a tomorrow that matches our extraordinary past. Ballot papers have now arrived on the doormats of 35,000 London Labour members and 400,000 trade union members – and it's they who must decide whether to offer London a new politics. If you're one of them, I'm hoping you will decide – as our Labour movement has done down the ages – that it's time to end the status quo, it's time for change. Only that way will we rid our country of this malign Tory-led government, and secure progressive politics for the future.

This Comment piece ran in the Guardian on 8 September 2010