Plans for the £9bn ($12.6bn) revamp of London’s underground network have been thrown into dissaray following the proposal to contractors to include an alternative scheme devised by the city’s new transport commissioner, Bob Kiley.

It was originally intended that client, LU would announce the successful bidders for the two deep line concessions last month. The concesions are the Bakerloo/Central/Victoria lines and the Jubilee/Northern/Piccadilly lines (T&TI last month). But at a meeting between prospective contractors and London Underground, groups were told that the appointment had been put on hold.

An estimated £15M ($21M) has already been spent preparing the bids for the deep line concessions by the consortia. The competing ventures for the Bakerloo/Central/Victoria line are the Linc team and Metronet. The Jubilee/Northern/Victoria lines contract has been narrowed down to TubeRail and TubeLines.