Eight out of 10 of London's main tourist sites will be inaccessible for the disabled by the time the 2012 Olympics are held, it has been claimed.
Forty-seven out of 275 tube stations have step-free access
The study by London Assembly Liberal Democrats found most London Underground (LU) stations in central London would not become step-free until 2020.
The report added 17 of the 27 Tube stations which will be refurbished by 2012 are in outer London.
A spokesman for LU said the report was "disappointing" and misleading".
Currently 47 out of a total 275 stations across the network has step-free access and refurbishment is under way in three more stations.
Dee Doocey, the Lib Dem's Olympics spokesperson, said: "Disabled athletes and visitors to the Games travelling on the Javelin trains from Stratford to St Pancras will not be able to continue their journey into central London to visit the capital's top attractions because most of the Tube stations either have steps or escalators.
"They won't even be able to use Piccadilly or Oxford Circus.
"It is time the London mayor ordered a major re-think on priorities and got work started on the stations that will really matter for the Olympics," she added.
By 2010, 25% stations will be accessible for disabled travellers and this figure is expected to rise to 33% by 2013; a substantial amount of work will be completed by the 2012 Games, LU said.
Half of all stations will have step-free access by 2020 but the facilities have to be spread across London rather than being concentrated in central London, it emphasised.
Richard Parry, a director of LU, said the Lib Dems report is "misleading" and that £1.5bn is being invested to make the network more accessible by 2012.
"They have misunderstood the position with step-free access."
"The underground is a relatively inaccessible network because of its long history. We have 47 stations that are step-free today and that will increase to 69 stations by 2010, which is a quarter of all stations," he said.
He also added that the aim is to provide an "overall transport solution" hence alternative modes of transport like the buses and DLR have been made accessible for disabled people.