Skyscrapers are go! Rogers plans futuristic tower to dwarf Lloyd's

The capital's skyline, already bulging with Norman Foster's half-finished "erotic gherkin" and awaiting a decision on Renzo Piano's "shard of glass" at London Bridge, faces yet another architectural eruption. Richard Rogers has plans for a tower and plaza complex with a futuristic vision that could be straight out of Thunderbirds.

The 700ft-high building would dwarf Lord Rogers of Riverside's iconic Lloyd's of London "espresso machine" building, which is directly opposite the development site at 122 Leadenhall Street.

Next to Tower 42, formerly the NatWest Tower, and Lord Foster of Thames Bank's Swiss Re building, the development would be part of the City's first big clump of skyscrapers.

The Government's Commission for Architecture and the Built Environment, emboldened by recent planning approval for the 43-storey Heron Tower on Bishopsgate, will no doubt view Lord Rogers' latest projectwith approval.

The Thunderbirds image is unavoidable but not necessarily pejorative. The tower will be a streamlined wedge of glass and steel connected to a partly separated gantry containing lift and service cores. The Rogers design, to be built in association with the developer British Land, is something new for London – San Francisco's Transamerica skyscraper is comparable. It appears to solve the serious problem of dead space under buildings of brio.

This might be because Lord Rogers dreams of a London made up of a patchwork of lush parks, brownfield developments, towers and piazzas humming with conviviality.

The building's surging upthrust might suggest an architect in the mould of Gerry Anderson's character Brains. In fact, the boffin at the heart of this scheme is Graham Stirk, responsible for the brilliant Lloyd's Register. He has taken Lord Rogers' mantra to heart: the tree-planted St Helen's Square plaza around the tower would also undercut it, creating public space in the City at street level and at first-floor height.

Will the Leadenhall Street project become fact or remain fiction? The most likely objector, English Heritage, could let this one ride for two reasons. It is heavily engaged in contesting the proposed 1,000ft high "shard of glass" and its main objection to Heron Towerwas that it would compromise sightlines to St Paul's Cathedral. There seems to be no such threat to the Rogers' proposal, with one proviso: the feasibility study document is light on pictorial detail.

But if the plan is approved, there is no doubt, nearly two decades after Lord Rogers' first London masterpiece, that the City would gain another iconic building.