The figure was contained in the 2050 London Infrastructure Plan launched by Mayor Boris Johnson yesterday.

The report sets out the full range of infrastructure requirements for the capital over the next half century, during which time the population of London is forecast to increase by 37% to more than 11 million people.

Johnson said: “This plan is a real wake up call to the stark needs that face London over the next half century.

“Infrastructure underpins everything we do and we all use it every day. Without a long term plan for investment and the political will to implement it this city will falter. Londoners need to know they will get the homes, water, energy, schools, transport, digital connectivity and better quality of life that they expect.”

If London’s population increases as forecast the plan explains how the city will be faced by a series of serious challenges to its infrastructure:

• Demand for public transport is forecast to increase by 50% with increased demand for Underground and rail services likely to increase by 60 and 80% respectively.

• Demand on energy supplies is set to increase by 20% during a period where demand on electricity supplies is forecast to more than double.

• Thames Water projects demand for water will exceed supply by 10% in London by 2025, rising to 21% by 2040.

• With an increasing school age population more than 600 new schools and colleges need to be provided.

• To meet the demand for housing around 50,000 new homes a year must be provided.

• With Heathrow already operating at 98.5% of its capacity, a new four runway hub airport in the Thames estuary must be provided to meet London’s wider social and economic needs.

Arup estimate that the total investment in London’s infrastructure between 2016 and 2050 could amount to £1.3 trillion.

A consultation on the London Infrastructure Plan 2050 will run for three months and the Mayor is expected to publish a final report in early 2015.

David Tonkin, Atkins’ chief executive officer for UK & Europe, said: “As a company which helps cities all around the world to create a better future for its people, we applaud the GLA and the Mayor of London for taking this step to develop innovative and integrated proposals to repurpose and reuse existing infrastructure, while adopting and applying new technologies and techniques.”

Steve Fox, BAM Nuttall CEO, said: “We are encouraged by the visible commitment made by the Mayor and the GLA to improving London’s infrastructure.

“It’s a strong signal to the industry and it gives confidence to major infrastructure contractors such as BAM who are heavily invested in London projects in setting our future business strategy. It means we can invest in people, training and our local supply chains across the capital to support the Mayor’s London vision in the longer term.