This rash of carbuncles

In an extraordinary outburst Charles criticised the Mayor's policy of encouraging the building of skyscrapers.

He claimed the capital was under threat of being "vandalised" and faced ending up with a "pockmarked skyline".

Echoing his famous "monstrous carbuncle" comment in May 1984, about a proposed extension to the National Gallery, the Prince warned of: "Not just one carbuncle, ladies and gentlemen, on the face of a much loved old friend, but a positive rash of them that will disfigure precious views and disinherit future generations of Londoners."

His stance conflicts with that of the Mayor, who has predicted that one skyscraper will be built every year, and there will be up to 20 tall buildings in the capital by 2015. The Prince spoke out at a building and planning conference at St James's Palace.

He said: "For some unaccountable reason we seem to be determined to vandalise these few remaining sites which retain the kind of human scale and timeless character that so attract people to them, and which increase in value as time goes by. Thus, in chasing the corporate tenant or buy-to-let investor, we may not only be destroying our heritage, but killing the goose that lays the golden egg, for we will destroy what makes our cities and towns so attractive to tourists in the process."

He suggested Canary Wharf was the best place for high-rise blocks, rather than locations where they overshadowed historic buildings.

He highlighted Berlin, where the authorities have restricted the height of new buildings. This approach could "help to achieve a far more coherent sense of harmony and civic self confidence than the free-for-all that will leave London and our other cities with a pockmarked skyline," he said.

In October 2006 Mr Livingstone said: "If you want to build a tall building, as long as you've got a world class design and it is one of two locations we will go along with it. When I was elected you had two tall buildings.

"I think you've now got nine and by 2015 you'll have perhaps 19 to 20. You're talking about one a year." Charles has blasted architects and town planners in the past for having a "cavalier attitude". His charity, The Prince's Foundation for the Built Environment, aims to improve quality of life through good planning and design. Its mission statements says: "We believe that if we can apply time-tested principles, building once more in a sustainable way, we will reap improvements in public health, in livelier and safer streets and in a more affordable lifestyle.

"We believe neighbourhoods exhibiting these sustainable characteristics will accrue higher value over time."

Charles was speaking today at the New Buildings In Old Places conference, in his role as president of the foundation and of The Prince's Regeneration Trust.