The current Billingsgate site (at Canary Wharf) will definitely be towerblocked (and, at a guess, not just with one), but most of Smithfield is Grade II* listed (the Poultry Market is Grade II) and will become a mixed-use development. There's definitely no danger of new tower blocks there. Benefits of the change of use may include returning the one-way system to two-way operation.
The current Billingsgate site (at Canary Wharf) will definitely be towerblocked (and, at a guess, not just with one), but most of Smithfield is Grade II* listed (the Poultry Market is Grade II) and will become a mixed-use development. There's definitely no danger of new tower blocks there. Benefits of the change of use may include returning the one-way system to two-way operation.