Mayor of London Boris Johnson has backed Irvine Sellar’s Seal House and Land Securities’ Walkie Talkie tower development plans in the City of London but is seeking significant Crossrail contributions from both developers.

Johnson’s planning office said it had reviewed and supported Sellar Properties’ revised David Chipperfield-designed plans to redevelop Seal House near Fishmonger’s Hall. He said the proposals would promote London’s ‘world city role and is positive in terms of economic development’.

However, the mayor’s office said it would require an increased s106 contribution from Sellar Properties as well as a Crossrail contribution of £213.30/sq m or £19.80/sq ft which on the 61,560 sq ft building equates to a payment of £1.2m. Transport for London will also require a contribution of £220,000 and a capped contribution towards bus stop upgrading works.

Land Secs’ slightly revised plans for its Walkie Talkie development at 20 Fenchurch Street also received broad backing from Johnson’s office although it said it did not meet ‘the highest standards of inclusive design and the applicant should address this to the satisfaction of the Corporation’.

It said Land Secs would be required to make around a £1.4m contribution towards Crossrail. Land Secs has already committed to providing nearly £1.2m towards pedestrian improvements, bus initiative improvements and a contribution to London Underground’s Bank Congestion Relief and Step Free Access proposals.

Both schemes are still awaiting a decision on planning consent from the City of London Corporation.