London's future skyline in doubt
The tallest skyscraper planned for the City of London may never become reality, its lead architect admits - as a BBC investigation raises questions over the capital's future skyline.
Amid the clamour that accompanied the completion of the Shard, something was amiss.
The UK's tallest skyscraper did not have a single financial tenant in place.
It was a far cry from the opening of the Gherkin in 2004 - all of that building's floors had been leased.
Now a BBC Inside Out study has found numerous major developments across the City that have run into problems.
At least six landmark projects - worth hundreds of millions of pounds - have been put on ice or cancelled altogether.
These include the 172m (564ft) 100 Bishopsgate skyscraper, on hold until developers secure enough advance tenants to make it viable.
Also on hold is the so-called Can of Ham, on St Mary's Axe.
It was granted planning permission in 2008 - but the building on its planned site has not even been demolished yet.
Architects Foggo Associates said developers were "waiting for the market to turn".
And a nearby scheme of futuristic office blocks, One Trinity, has been abandoned completely. The existing office on the site will be turned into a hotel instead.
But arguably the most prestigious building to be halted is the Pinnacle - nicknamed the Helter Skelter.
At 288m (944 ft) it would have been the second tallest skyscraper in the UK, towering over Canary Wharf's One Canada Square.
Construction on the Pinnacle began in 2009, but has repeatedly stalled.
Work is not due to resume until 2013 - by which time it will have stood less than half-built for almost 12 months.
Left in the City is a 10-storey concrete pillar locals have dubbed "the Stump".
A legal fight is under way between the contractor and developer of the 63-storey, £1bn tower.
Now one of the lead architects in the original project has voiced his doubts that his creation will become reality.
Lee Polisano told the BBC: "My own belief is the building that gets built will probably be a different building to that there at the moment.
"It is a shame that we have a very important piece of land at this key site that's empty."
Mr Polisano designed the tower for architects KPF before founding his own firm PLP, and is no longer involved in the scheme.
He continued: "It is logical to understand in these economic times a building of that sort is a difficult building to make financially, so I am not surprised to see something so ambitious being stopped."
None of the developers involved in the project have commented.
But Jerry Swain, regional secretary of the Union of Construction, Allied Trades and Technicians, claimed the troubled scheme exemplified the problems for those working in the building trade.
He said: "The Pinnacle is perhaps the biggest example of this recession.
"It's like the hokey cokey for workers - they are in they are out, they're in they're out.
"It's just unbelievable to watch that project - it's become farcical."
Meanwhile, newly-completed and prestigious buildings in the City lie empty.
They include Cannon Place, which does not have a single tenant, although the developer said negotiations are ongoing.
And the nearby Walbrook building - completed in February 2010 - has only let a sixth of its 445,000 sq ft of space.
A spokesman for the project admitted the current times were "challenging".
The other developers surveyed by the BBC are yet to comment.
Three landmark projects that have become reality are the Heron Tower, Cheesegrater and Walkie Talkie.
All have managed to secure tenants - now a prerequisite for building.
Kaela Fenn-Smith, a spokeswoman for the Walkie Talkie - at 20 Fenchurch Street - said the secret to getting a development off the ground was "location and timing".
That was echoed by Simon Rawlinson, a leading property development consultant at EC Harris.
He explained: "At the moment if you don't have a tenant you don't have a project, so you don't bother.
"Projects have been cancelled or delayed in the past 12 months because they thought they had a pre-let and that fell away. Those projects had to be mothballed.
"Getting the tenant is absolutely critical."
Mr Rawlinson added: "Getting money to develop now is harder than it has been in 20 years."
City bounces back'
The completion of the Walkie Talkie and the Cheesegrater will bring to an end the current cycle of skyscraper development.
But Peter Murray, chairman of London's Centre for the Built Environment - an architectural forum - sounded a note of optimism.
He said: "I've seen four recessions during my career - and in each one I've heard people say, 'Look at all this empty office space, why do we need it?'
"And after each one as the economy has improved, it has become occupied.
"In the long term I am very optimistic about the City, because the City has shown throughout history that it is able to deal with pestilence, bombing, blitzes, fires, all those things.
"It bounces back."
BBC Inside Out is on BBC One in the London region on Monday, 19 November at 19:30 GMT and nationwide on the iPlayer for seven days thereafter.