Elbowing in behind the Cheesegrater and the Walkie Talkie, London's latest skyscraper 22 Bishopsgate will fill a desperate need for office space in the City after new designs were revealed.

The aesthetic quality of the designs "pales into insignificance" when put up against the urgent need for more office space, said Peter Rees, the City of London's former planning officer, who retired to become a professor of city planning at University College London in 2014.

"The City is desperately short of office space," with a vacancy rate of 5%, he said, noting this is well below the minimum healthy amount of 8%. "The City is running out of space."

Buildings like 22 Bishopsgate, at 278m tall and 62 floors, are the answer, Rees maintains.

The new design by Lipton Rogers, and owned by AXA Real Estate, has been a long time coming. Work on what was to be The Pinnacle came to an end three years ago in 2012 when developer Arab Investments' deals to sell off parts of its 90% stake in the building came to nothing. Construction had begun in 2008. All that was left was a deep foundation and the stump of an elevator shaft. These will now be demolished if 22 Bishopsgate is approved.

That approval should be set on the fast track, Rees said, noting approvals should go through "as quickly as possible because the market is desperate for space".

The new designs are likely to go to planning committee in the next couple of weeks, said a source inside the City of London, with "a high chance of approval" likely to be made in September or October.

The City has a rigorous pre-planning application process, so any designs at the committee stage have been well considered, they said.

They cited the vacancy rate at 4% and noted that new buildings like the Cheesegrater and Walkie Talkie which both opened in 2014 have almost been completely let.

In its report for the first quarter of 2015, property analyst Knight Frank put commercial vacancies in the city at 5.7%, but said this is the lowest it has been since 2001.

Aesthetics, of course, do play a roll when landmark buildings like this go up. Rees said that the Pinnacle, with its twisting design that he nicknamed the Helter Skelter to the consternation of the buildings owners, had a purpose behind it.

"The Pinnacle was meant to be the centrepoint of the cluster of towers," he said, and was intended "to be a landmark" that stepped down to St Paul's and the bank of the Thames.

The new proposal is a "more functional building" with standard office accommodations, he said. It has "less curves, less complications".