More than 200 towers rising to 20 storeys or above are planned in London over the next two decades.

Up to 150 of them will be residential towers, transforming the capital into a high-rise city, but the planning system is ill-prepared for them and the public largely unaware, English Heritage has warned.

This wave of planning applications has sparked calls for clearer planning guidance and greater effort to encourage public debate about the planned transformation of the London skyline.

Roger Barker from English Heritage warned this could result in a ‘wall of development stretching from Vauxhall through to Southwark’, with perhaps a dip at the South Bank.

Speaking at the launch event for a planned new exhibition highlighting the changes called ‘London’s Growing…Up!’ this April, he said that tall buildings were being used too much by their proposers as the ‘panacea’ or answer to several problems.

Architectural rendering studio Hayes Davidson has created images of how the Square Mile could look in 10-15 years time.

But the architect for London’s tallest residential building has defended the spread of high-rise south of the river from its traditional home of the Square Mile and Canary Wharf.

Peter Vaughan, director at architectural practice Broadway Malyan, said: “In the absence of planning frameworks we shouldn’t be surprised that developers believe their site is a good location for a tower.

“In the absence of a ‘no’, developers understandably assume ‘yes’ and until a city-wide framework sets out what is possible long public enquiries will continue to be required to judge experiments.”

He added: “The idea of ‘jumping the river’ is inevitable and entirely right given that historically some of the most impoverished London boroughs, with the space and opportunity necessary for tall buildings, are south of the river.”

Vaughan said that predictions of a ‘wall of high-rise buildings’ running down the southside of the Thames were overblown.

“Real estate has always been currency and today’s gold standard happens to be London residential.

“But there won’t be a ‘wall of development’ south of the river due to the constraints that do exist.

“However, there are clear opportunities for needle and point buildings, rather than clusters of tall buildings, at key river crossing and transport interchanges.

“The tall building clusters that exist in The City and at Canary Wharf are such for particular reasons – sitting inland of the river. It’s interesting to see that the Walkie Talkie has crossed the road southwards, revaluing the entire street.

“The South Bank, can and should, accommodate a ‘ribbon of high points’ in contrast to the constrained environment north of the river.”

 London’s Growing… Up! exhibition, starts 3 April at the Building Centre.