Two thirds of people in Harrow are forced to travel more than a mile to their nearest public pool - making the borough's access to swimming among the worst in London.
Only residents in Redbridge, Hillingdon and Havering are worse off when it comes to distances to local baths, with Harrow boasting just three public facilities.
The findings, produced by London Assembly's economic development, culture, sport and tourism committee, was conducted in light of plans to promote swimming in time for the London Olympics in 2012.
However, facilities in Harrow are now unlikely to improve in time for the games because of the crisis in the economy.
Harrow Council had made provisions to bring in two new pools across the borough, renovate the facilities in Hatch End and build a new leisure centre - but these have all been shelved.
Councillor Chris Mote, who is responsible for community and cultural services, said: "We were looking at where we could bring in new pools and had already taken this kind of feedback on board. Obviously we want to spread facilities evenly around the borough, but this just isn't going to happen now.
"It's incredibly annoying but unfortunately in the current economic climate it's just not possible."
The council had looked into finding space in South Harrow to accommodate a new pool to add to current facilities at Harrow Leisure Centre, Wealdstone, The Aspire Centre in Stanmore and Hatch End Swimming Pool - but that too has been scrapped.
In total 65 per cent of people in Harrow have a walk of more than 20 minutes to their nearest pool, which compares badly to similarly sized boroughs such as Islington and Hackney where the figures are just three and 12 per cent respectively.
Harrow is also among the 24 boroughs in London criticised by the report because of its complete lack of diving facilities.
Despite being unable to open new sites, Mr Mote has signalled that the council is looking into making swimming free for those over 60 and under 16 - after a similar programme was successfully rolled out over the summer.
The council has just learned that it will receive £164,000 in funding to implement the scheme.