Speaking at a briefing on the proposed revisions to the London Plan, John Lett, strategic planning manager at the Greater London Authority (GLA), revealed that the mayor’s upcoming, long-term '2050 Infrastructure Plan' would be "asking unmentionable questions".
He said: "It will be asking: Where is London going to grow? What’s the infrastructure needed to support that growth? It will be looking at green belt development, new towns, expanded towns."
Lett also promised that it would look at the possibilities of airports closing and new ones opening.
He added: "These are issues that are outside the planning system, but this debate is beginning."
Last July, the GLA revealed that the mayor would publish a strategic infrastructure plan alongside a revised version of the London Plan.
According to the GLA, an interim report on what it describes as a long-term infrastructure investment plan is due this spring with a final report in the summer. It has said the plan would consider London’s needs up to 2050, examining a number of scenarios including airport locations, densities and the impact of technological change.
Meanwhile, the draft Further Alterations to the London Plan (FALP), published in January for consultation, raises the capital’s housing target to 42,000 homes a year up to 2036, up from 35,000 a year in the current plan.
At the event, organised by business group London First and hosted by consultancy CBRE, Lett also said the GLA was "very concerned" about the loss of offices to homes. He said this was taking place as a result of both new office-to-residental permitted development (PD) rights and the "operation of market forces".
In central London, Lett said the exemption from the new PD rights, granted by the government last year, "hasn't been working as well as we thought it would", As a result, the FALP allows boroughs to introduce "where justified" policies to protect smaller-scale offices.
Lett also said the GLA had "severe technical reservations" about the government’s latest household growth figures, which he said anticipate 52,000 new households a year in London over the plan period.
He said the GLA would challenge the Department for Communities and Local Government (DCLG) about this at the FALP’s examination in public later this year
A "much more realistic approach", Lett added, taking into account changes in fertility and outward migration trends could result in a much lower increase of 40,000 households a year.
But he said the possible range was between 40,000 and 62,000 a year and the GLA "genuinely don't know" what the exact figure could be.
Lett said London was facing an "unparalleled increase in population" but said the rate of growth "could be a short-term phenomenon". He pointed out that the recession meant that outward migration from London of families and older people had reduced significantly.
Also speaking at yesterday’s event was Stuart Robinson, CBRE’s head of planning and chair of the London Office Review Panel, who said the "major threat" facing the capital’s offices was high residential land prices which hastened their conversion into homes.
He also expressed concerns about the impact on development of the high levels of the Community Infrastructure Levy that some London boroughs were proposing to charge on top of the mayor’s levy to pay for Crossrail.
"We've seen some areas where demand could be wiped out with the levels some boroughs are promoting," Robinson added.
More information on the GLA's infrastructure plan can be found here.