Property developers are facing a crackdown on ambitious plans to build skyscrapers beyond the City of London.

The Government is poised to rein in what has for the past few years been seen as a liberal London planning regime, which has given the green light to a number of planned high- risers, such as the 310 metre (1016 ft) Shard of Glass over London Bridge.

But following a severe reprimand from Unesco in a hitherto unpublished report, the Department for Media, Culture and Sport has indicated in its own interim report, seen by The Times, that it will rein back on approving plans for more tall buildings in Westminster and Southwark.

An imminent change in government planning policy could set it on a collision course with Ken Livingstone, the Mayor of London, who has been an advocate of more skyscrapers throughout Central London in his backing of “the London Plan”.

The Unesco world heritage committee report, compiled last July, lambasted the UK Government over the lack of protection for what it considers to be London’s international historical landmarks, from the Tower of London in the east to Westminster Abbey and the Palace of Westminster in the west.

In a side-swipe at the London Plan, Unesco said that it “regrets that the London Plan policies to protect the World Heritage property and its environment do not seem to be applied effectively [and] that statutory protection for views to and from the Tower could be diminished”.

The Unesco report also urged the Government — referred in its report as the “State Party” — to “review the possibility of inclusion of the property [the Tower of London and Westminster Abbey] in the list of World Heritage in danger”.

Unesco also called for statutory protection for the view from the South Bank towards the Tower of London.

“To keep the last remaining visual axis unobstructed is key to the conservation of the visual integrity of the Tower,” it said.

However, the Culture Department has said in its interim report: “The UK state party is pleased to report a new protected view of the Tower of London is to be included in the London View Management Framework.

“The precise detail of the protected view is under discussion between key stakeholders and we will forward a plan that defines it as soon as it is agreed.”

The documents were submitted in a planning inquiry for a new London skyscraper.

The Government also reported to the planning inquiry that “a visual impact study of the World Heritage Site [Westminster Abbey and the Palace of Westminster] is to be undertaken as requested by the mission [Unseco]. The findings of the visual impact study will inform revision to planning policy at both the regional and local levels as well as being an important national consideration in determining future applications”.

A likely tightening of planning policy on tall buildings could undermine proposals already stuck in a planning inquiry to build the 180 metre Beetham Tower on Blackfriars Road, rising to 52 storeys and including a 261-room hotel. Initial plans for a a 226 metre tower were scaled back.

Changes in planning guidance will threaten proposals yet to be submitted to erect three towers, called Elizabeth House, rising to 140 metres next to Waterloo station.

Land Securities, Britain’s largest property company, is also thought to be working on plans to build twin 50-storey towers near Victoria station, which could dominate views of Westminster Abbey and Buckingham Palace.

Land Securities last year submitted a multibillion-pound scheme for Victoria station, which included three skyscrapers ranging between 25 and 42 storeys. The scheme was withdrawn when Westminster council made it clear that it would allow only one tower above 12 storeys.

Towers in trouble

- LandSecs’ plans for its 525 ft “Walkie Talkie” tower in Fenchurch Street. Corporation of London approved the scheme in September outside the designated “cluster” for tall buildings but the Government has called in the plans. Ruth Kelly, Minister for Communities and Local Government, said she would look at the "appropriateness of a very very tall building" in the area and its impact on the Tower of London.

- Plans under review for the 180m Beetham Tower on Blackfriars Road.

- LandSecs is thought to be working on plans to build a pair of skyscrapers near Victoria station.

Times Recommends

• C&G axed - 1,660 jobs to be lost
• UK house prices rise 1.1% as buyers return
• Mixed reaction to US banks repaying bailouts