Tessa Jowell was MP for Dulwich and West Norwood from 1992 to 2015. She was in charge of the bid and delivery of London 2012 Olympics, and is a former Minister for London.

While I was out knocking on doors on polling day, a party activist showed me the health app on his iPhone. By the end of the day he had walked an incredible twenty-eight kilometres and climbed thirty-five flights of stairs. Suddenly I felt a lot better about missing my morning gym session.

London faces huge challenges, from housing to infrastructure to low pay, and solving them will require major changes to the way our city is run. But a better future for London means lots of smaller changes as well – incremental shifts that might not excite newspapers but can improve lives and shape communities for the better. Together these changes can add up to major benefits – what Dave Brailsford of Team GB cycling terms “the aggregation of marginal gains”.

Eleven years ago, Ken Livingstone as Mayor developed a plan to make London a truly walking-friendly city. While progress has been made, we need, for a number of reasons, to renew that vision and redouble our efforts to get more Londoners on their feet.

First, as Steven Norris points out in this volume, London’s population is booming: by 2030 we are expected to qualify as a ‘megacity’, reaching the 10 million-threshold. This population growth is putting huge pressure on our trains and buses, roads and streets. Of all modes of transport, walking places the least demand on our transport networks and environment. Indeed, where almost all other modes of transport detract from our environment, making London’s uniquely rich public realm less safe and welcoming, walking has the opposite effect – more people on the streets means safer streets and more of the social interactions that bring communities together.

For the mother pushing a pram, for older people seeking fresh air, or for people for whom strenuous exercise is simply too much, walking is a great way to get out of the house and stay active

Second, we face a public health crisis in London, with unhealthy lifestyles and obesity on the rise. Walking can play an important role in tackling this. The recommended level of physical activity per week for adults is 150 minutes, and about 25 per cent of adults in London get those 150 minutes from walking and cycling – but this could rise to 60 per cent if we could get more people to bike, run or walk short trips. For the mother pushing a pram, for older people seeking fresh air, or for people for whom strenuous exercise is simply too much, walking is a great way to get out of the house and stay active.

Finally, while walking is, of course, the oldest and least high-tech mode of transport, it is being enabled by new technology. Twentieth century visions of future cities variously featured jet-packs, mini-helicopters, self-driving pods and other magical devices. But in a way no one expected, technology’s advance is not making walking obsolete – in fact, it’s making it easier. Where once we needed a good sense of direction or a paper map to navigate unfamiliar streets, today we need nothing more than the smart phone in our pocket. Pedometer apps and devices are becoming a keep-fit staple for millions of us. If you can measure it, you can track it, and if you can track it, you can set yourself the targets and goals that make an exercise regime easier to maintain and more fun.

So how can we create the space for Londoners – and visitors – to get walking? There are four things we need to do.

First, we have to make walking a positive experience. That means clean, well-lit streets and signposted routes, accessible for those with mobility issues and other impairments – people have to feel safe and secure. And the air pollution that blights our city must be tackled. We have seen how closing Oxford Street to traffic has benefited businesses and walkers; now we need further similar experiments in prioritising the pedestrian experience. Groups like Sustrans and Living Streets have facilitated some great projects which show how to make streets people-friendly at a relatively low cost. We can learn too from Barcelona, which has introduced new pedestrianised and car-light zones.

Second, we need to harness London’s entrepreneurial spirit to develop technologies that drive behavioural change. One idea would be a London incubator focused on active travel, building on the success of places like Google Campus (a ‘space for entrepreneurs’) or Bethnal Green Ventures (a three-month ‘accelerator programme’ that invests in and supports teams to help build solutions to social and environmental problems). Parkrun, a free, grassroots running event, began in West London’s Bushy Park and now operates hundreds of weekly races throughout the world; the Citymapper travel app started here too and has now gone global. There is definitely room for more success stories like these. With endorsement from sports teams or major leisure brands to help drive awareness, I want City Hall to provide new policy incentives to make London the best place in the world to develop ‘active’ start-ups.

Could we change the last mile of trips between rail terminals and central London to encourage more walking and reduce tube and bus crowding?

Third, we need to target our resources. For instance, could we change the last mile of trips between rail terminals and central London to encourage more walking and reduce tube and bus crowding? Providing clear, safe, signposted running or walking routes between stations including Waterloo, Charing Cross and London Bridge and popular Zone One destinations would alleviate the challenges brought by waiting to get on trains, tubes or buses to complete journeys to work. Commuters could be confident in how long their journey would take while getting some exercise and fresh air.

Finally, we need to do more to encourage walking’s more energetic sister: running. The commuter runner is a growing phenomenon: a study by the University of London’s Royal Holloway shows that the number of people choosing to run to or from work has tripled in the last two years. There is much a Mayor could do to encourage commuters to swap their trains for trainers, including encouraging employers to invest in showers and changing facilities for those who run to work.

Other cities are leading the way – we could learn from the boulevards of Paris, the High Line in Manhattan or the straatjes of Amsterdam. In Rotterdam, a crowd-funded elevated pedestrian bridge is connecting parts of the city that have been dislocated by railway lines and busy roads. And in Raleigh, North Carolina, the Walk [Your City] project is enabling citizens to generate attractive, custom-made street signs to show the calculated minutes of walking from one point to another, both increasing walkability and building a sense of community.

The delivery of changes like these cannot rely solely on top-down direction from politicians – we need to build a movement of active walkers who will campaign for better public spaces. Pro-cycling groups are achieving some great things in London; an engaged community of walkers could have an even more profound impact.

Getting more people walking could be the small change that heralds a big improvement for our city.