Deep in London’s DNA are core ideas about how we live together. Living by a major river requires certain obvious forms of cooperation — from the management of tides, winds and water levels to the protection of wharves and moorings or rules and codes through which to share space. Living by a river requires a social contract between all those involved.

As population expanded around the Thames, the built environment became the key enabler of development. Bridges and wharves, homes and offices, markets and exchanges, and eventually railways, tunnels and roads enabled our expansion.

London’s long history of negotiating its preferred place within the realm really took off in 1067 with the charter between Norman King William I and the City of London. The rights to trade and associate were enshrined in return for loyalty to the King.

Since then, London has been through multiple cycles, and that ‘contract’ has been tested and revised. Plague, fire, rebellion, war, battle, bombing, stink, smog, flood and contamination, as well as the losses of empire, industry and population, have befallen the city on multiple occasions. Yet London has proved resilient.

London has developed the capacity to enrich lives through connections, opportunity and experience. Anyone can become a Londoner if they move to the city, as long as they adopt its ‘live and let live’ mindset and are open to its cosmopolitanism and quirkiness.

London has traded for many years on an implicit promise. If you come here and work hard, you will have the chance to ‘get on’ and ‘move up’. London life, the promise implies, will be underpinned by services, amenities and places that work — the NHS, the London Underground, the Met Police, schools, colleges and universities, the royal parks, the waterfront, the gathering places of squares, stadia, venues, museums, galleries, places of worship and humble, quirky, engaging street life. London’s promise is that you will work hard, but the city will repay your effort.

For much of the last quarter of the 20th century, London broadly fulfilled its promise as jobs grew, schools improved and homes were built or regenerated. London proved able to attract new talent and investment, acquire new jobs, generate taxes and expand its media, cultural and educational roles. London did this by embracing globalisation, first in services, finance, media and information, then in talent and capital, and latterly in enterprise, creativity and innovation. From the early 1980s to today, some 40 years later, London’s population grew from 6.9 million to 9.65 million.

The London promise has been challenged by the COVID experience. It revealed the immiseration of the people through unaffordable housing, insecure jobs, unfair treatment, unbreathable air, extreme inequalities and many other sharp disparities.

The social contract is the tacit agreement about what is necessary for the collective endeavour of a free society to meet the needs and protect the wellbeing of its citizens. This can include the protection of civil liberties and sanctity of human life, the desirability of opportunity for all, freedom from slavery, the right to a fair trial and respect for privacy. It is the overall combination of rights and responsibilities. These are the things that make up social contracts in much of the world.

The rights of businesses to produce, trade, invest, employ, sell and enjoy the profits of doing so are subject to the new social contract. Broadly speaking, businesses must do more good than harm, and they must not damage the carefully crafted matrix of rights and responsibilities that society fosters. This is what gives a business its license to operate.

In our modern world of ongoing rapid urbanisation and planetary peril, the built environment will only grow, thrive and succeed if it fosters the social contract that in turn enables it.

As I described in essay one of this series, the big shift in the post-pandemic city is towards recasting our value as habitat, innovation and experience, underpinned by a fresh approach to place leadership.

This is encouraged by a growing recognition of the potential of social capital and agility to both help us remake our city and also foster new forms of value creation. In London, our experience has been that the most successful reinventions of place have been ones where high social value has been central to the mission, leading to a high-trust and high-confidence approach that has ‘crowded in’ people, communities, amenities and, consequently, other forms of capital. It is already clear what some of the features of the new social contract for a world city need to be. We might highlight 10.

1. There is a new mandate for clean air and a healthy city, both to protect human life and to respect our planet and all of its other inhabitants. The return to the primary issue of human health and its link with planetary health is not a surprise post-pandemic, but the recognition of the severity of the challenge we face is.

2. We need mixed-income neighbourhoods and a diverse city if we are to maintain the social and creative fabric that makes London so rich. We don’t want to ‘sleepwalk’ into homogenous districts and neighbourhoods. To fix this we need a revolution in housing supply and attainability. London’s advantage for 50 years has been its social mix, but it is clear that housing market dynamics will not on their own reproduce that mix, so much greater shaping will be required.

3. We must tackle the problem of spatial justice and postcode lottery that sees different opportunities defined by address. The spatial character of life- expectancy in London is stark. In the boroughs with the lowest, men and women can expect to live seven to 10 years less on average than those with the highest.

4. Our city and places will be safe for women and girls, day and night, with the increased social justice and productivity it will bring. Violence and other crimes against women and girls are blighting lives, making our streets and public spaces less safe, undermining our public transport and reducing our labour market participation.

5. A fresh deal between employees and employers to find a new bargain between flexibility and productivity, enabled by physical place and digital space, will need to be achieved. It needs to start right now, because the absence of clarity makes people, families and firms invest in models that may not be sustainable.

6. The motor car will not have the privileged place in our city that it enjoyed in the past. It will increasingly be a. niche mode of transport, usually shared, on demand, electric and functional, with much less physical space allocated to it. But for this new regime to be achieved we must inspire people to use other forms of transport and to embrace different ways to live.

7. Public space will be expanded to cover much more of our territory and be dynamically activated to provide shared experiences at different times of day and year. Public space and street life are the lifeblood of any city. London has incredible assets, but not all of them are optimised. From the Thames to churchyards, and from our many squares to our local roads, the new imperative for activated public space is key.

8. Fairness at work and in public services will need to be ensured through enhanced leadership and investment. The dramatic exposure of failures and inequalities in our health systems, policing and public safety, social care and education have resulted in low public trust that can only be rebuilt through new leadership.

9. London’s relationship with the rest of the UK will be reworked to be based on mutual recognition and respect for the unique and distinctive roles each place can play in our small and highly populated islands. Rather than a dramatic zero-sum or binary approach, we will need to emphasise how each place relies upon and is supported by others, and how we can shape those relationships to mutual advantage.

10. We will deepen our commitment to our ‘live and let live’ philosophy, reinforcing it as a source of social innovation that underpins all other forms of success. It was this ethic that led London to invest in schools, hospitals, public housing and much more in the past. We will need to do so again.

The built environment will play multiple and important roles in this new social contract. Much more than a hosting fabric for what London does, it is rather an intelligent body that enables the city to work by fuelling, weaving and coordinating all the city does. The core change is that the built environment, or physical space, is now recognised as an eco-system that can be agile, intelligent, sympathetic, inclusive, sustainable and resilient. It has personality. We have shifted from the built environment as a collection of passive assets to a city fabric that is dynamic as a platform, a service and an experience. In practical terms, the built environment that is needed to pioneer the new world city will have a distinctive character.

11. The decarbonisation of all buildings will be driven by market sentiment and laws that drive out carbon and increase residual values. Embracing circularity in the built environment will require us to revise the valuation systems for buildings. It will become both socially and financially unacceptable not to decarbonise, and we will see both incentives and sticks to make it happen.

12. We will optimise the scope of existing infrastructure investments (such as stations, waterfronts and town centres) to make our interchanges places of great concentration and vibrancy. These interchanges represent a key opportunity to optimise existing infrastructure investments more skilfully.

13. Housing mix and supply will be addressed by a revolution in medium-density, high-amenity, mixed-income living in new locations across London. This will require us to optimise development opportunities and inspire much larger redevelopment opportunities close to transport links.

14. The ground floors of all buildings will become spaces for all, and we will need to recognise the new balance between public and private space, with an emphasis on space that can be ‘civic’, playing different roles at distinctive times of the day and days of the week.

15. Public space, safety for all and shared amenities will revive the essence of London life. Agility will produce more forms and formats for public space, many of which will not necessarily be permanent.

16. A new flexibility and agility in building design will lead to places and spaces that are almost infinitely adaptable to additional or alternative uses. Rather than invest in fixed structures and uses, we will build facilities that can evolve and morph in different directions as needed.

17. Public land and buildings will not be idle spaces but be optimised for public benefit so communities can thrive. We will see many more public landowners using their land to build a fairer, cleaner and more accessible city.

18. New cycles and new forms of investment for a growing city will foster new ways of creating the urban fabric we need. This will include new forms of mutual investment to increase affordable housing, impact investing that will be more attractive than extractive investment, and new ways to tap the value created in the built environment in order to share it with the wider city that supports it.

19. Digitisation will enable a new matrix of connected places, optimising the interplay of digital and intelligent platforms with created and physical spaces. This means that rather than having to choose between digital and physical we will simply discover many more ways to integrate both.

20. We will commit to shared place leadership, to shape change in neighbourhoods and districts in the combined interest of common owners and users. If agility is our secret weapon in seeking to rebuild our city around the core ideals of habitat, innovation and experience, then place leadership is the organising platform to do so.

As we move towards 10 billion people living in 10,000 cities by 2100, revising our built environment leads to an opportunity for London not just to remake our city but also to lead the world on how all cities can be remade. London can be the leading hub of good urbanisation. It can compete with and serve other cities in generous and inspiring ways.