Plans to build a 16-storey tower block on top of Liverpool Street station have been described by actor and campaigner Griff Rhys Jones as “frightening” and “greenwashing of the most blatant kind”.Sellar, the developer responsible for the Shard at London Bridge and the Cube beside Paddington station, wants to erect a modern office block on top of the Victorian mainline station and the Grade II*-listed former Greater Eastern Hotel, now the Andaz hotel.Network Rail, which owns Liverpool Street station, supports the plans as they would fund new lifts and escalators in the station concourse, which it claims suffers from overcrowding at peak times.But conservation groups have joined forces to mount a legal challenge against the proposal, with hundreds of people attending a campaign meeting on Tuesday night.Mr Rhys Jones, president of the Victorian Society, said the plans would wreck an exemplary upgrade of Liverpool Street station only completed 30 years ago.He said the developments at London Bridge and Paddington were alongside, rather than on top, of the rail stations, as would be the case at Liverpool Street. “The precedent that this is setting, and the idea of what this means to conservation areas, and to buildings generally, is really frightening,” he said.He said the developer’s claims of new jobs and sustainable construction was “‘greenwashing’ of the most blatant kind”. He said the proposed development would leave the station and hotel “dwarfed, swamped and extinguished”.Mr Rhys Jones said 11 skyscrapers were already planned to be built in the City. “This is one project too far,” he said.