This has been on hold for at least several months as Brookfield is still looking for a tenant. I don't know much about London's commercial real estate, but the 36 story Walkie Talkie doesn't have any tenants, neither does the Shard's commercial portion, and Leadenhall is 1/3rd full.
Here's some disturbing news though, looks like Brookfield is redesigning the tower.
On Property: Brookfield rent war is Pinnacle of Shard’s problems
29 June 2012
"...The builders of The Pinnacle are revising costly designs for the £950 million tower in Bishopsgate.
The aim of Brookfield Multiplex is to wrest control of the stalled development from Middle Eastern investors. A spokeswoman for the Canadian-owned contractor confirmed, “we are re-designing the tower”.
Architect Kohn Pederson Fox is re-working plans to simplify the cladding on the 945-foot tower.
The aim is to save at least £50 million on the £550 million construction cost. But that’s only part of a plan to make the development viable by slashing the total cost from £950 million to £700 million.
Another £200 million saving would come from wiping out the liability to repay the original investors, who bought the site in May 2007..."