The AJ can exclusively reveal the nature of the next extraordinary design to be unveiled for the City of London.
Rafael Viñoly's proposals for a high-profile site in the Square Mile are set to go before corporation planners this summer.
The architect plans to demolish an existing 20-storey tower - visible from a large swathe of the capital, including south of the River Thames - and build an iconic 45-storey structure in its place.
The scheme was threatened after it ran 35 per cent over budget last year.
But it is understood that Fosters director John Drew was drafted in under the supervision of developer Land Securities - which owns a cluster of buildings in the area - to get the project back on course.
The new landmark will resemble a huge, curved television facing the Thames, or a seminal phone design from the 1950s produced by Swedish manufacturer Ericsson.
Engineers have had to cope with accommodating the equivalent force of three hurricanes to make the 'synclastic' (curved in two dimensions) structure stand up.
A special facade has had to be developed to cope with the building's unique shape.
Experts working on the scheme claim that the design had been complicated by Viñoly's insistence on a pervasive use of glass for this element of the building, which also incorporates a 'triple-wall system'.
The new, more stringent Part L regulations being introduced in April have forced Viñoly to rethink his planned widespread use of glass, and this problem has now been addressed.
This might not be as problematic as it may initially have seemed. The building's unique shape allows the upper floors to shield lower parts of the structure from the sun.
This will appease the money men as much as the environmentalists - with more office space in its upper storeys than its lower it will maximise any financial pay-off through premium rents.
According to corporation planning chief Peter Rees, the new structure will be the smallest of an existing cluster in the City of London - 'well below the city's glass ceiling' - shorter than the 200m-tall Gherkin, although still visible across London.
Rees says: 'I have to say, Viñoly is an extremely exciting character to work with. I have never known a meeting to even get a smidgeon dull when he's around.
'In general, I am keen to see a broad range of architects working in the Square Mile.
I don't think this site is going to disappoint.' Rees said the structure most reminded him of Ericsson's 1954 'Ericofon' - a design that integrated a telephone's earpiece, mouthpiece and dial into a single sculptural form.
According to sources working on the project, the tower is 'deferential' to the Tower of London and a nearby listed church, an issue that is a common bone of contention with English Heritage, which will no doubt strive to protect views of any heritage site that may be affected by a significant structure.
The site is known to have a colourful archaeological history, being at the end of one of the Roman roads that once bisected London. In addition, the future of Medieval 'deposits' has had to be addressed.
The building will replace an existing building by CLRP Architects which was once occupied by financial services firm Kleinwort Benson.
This 1968 building is 20 storeys of 'sheer curtain walling', according to Pevsner, finished by a distinctive dark band projecting over a recessed roof storey.
The Twentieth Century Society does not have a case file on the CLRP building, at 20 Fenchurch Street, so at first glance it seems Viñoly will be in for an easy ride. The scheme is thought to have received positive comments from CABE and English Heritage.
The tower will join other high-profile proposals for skyscrapers in central London, designed by the likes of KPF, Renzo Piano, Grimshaw and Richard Rogers, all of which have made headlines in the past 12 months. What Rees calls a 'fruit basket' approach to design - whereby a variety of landmark designs scatter London's inner quarter - is one of his principal hallmarks.
Viñoly has also courted publicity with his similarly exotic proposals for the site of the World Trade Center in New York, as well as getting the go-ahead for a visual arts centre in Colchester earlier this month. His UK offi ce recently expanded to 35 people to accommodate British schemes.
The cost overruns experienced by developer Land Securities are not unique.
Viñoly has recently become embroiled in a row with the Kimmel Center in Philadelphia over his budget. The US arts facility has claimed that in dealing with Viñoly it spent $23 million (£13 million) more than it should have done.
Whether Land Securities has been able to get its money's worth will become clear this summer. Viñoly is known to be working with Expedition Engineering's Chris Wise, who was keen to allay any fears that the project wouldn't meet its targets. 'We're well on track, ' he said.