The NHS trust which runs St Thomas' Hospital has stepped up its battle with Transport for London over plans for segregated cycle lanes on Westminster Bridge.
Patients and staff joined a protest outside St Thomas' Hospital on Tuesday morning as Guy's and St Thomas' Hospital warns that it could seek judicial review of Transport for London's plans for the bridge.
Vauxhall MP Kate Hoey joined the protest and urged TfL to think again.
In March this year TfL confirmed its proposals to change the layout of the junction at the southern end of Westminster Bridge, and to create segregated cycle lanes on the bridge itself.
NHS bosses claim that vulnerable patients arriving at the hospital by bus will be intimidated by the prospect of crossing a cycle lane between the bus stop and the pavement.
Guy's and St Thomas' NHS Foundation Trust has collected around 1200 signatures on paper and online petitions against TfL's proposals.
"We are not taking this action lightly, however we believe that TfL's plans for cycle lanes and so-called 'floating' bus stops on Westminster Bridge pose risks to both pedestrians and cyclists," said Sir Hugh Taylor, chairman of the trust.
"We are concerned about the impact on patients and carers, especially the elderly, disabled, and families with children in buggies and wheelchairs coming to Evelina London Children's Hospital at St Thomas'."
Jenny Stiles, vice chair of Waterloo Action Centre, added: "As a publicly elected governor of Guy's and St Thomas' and a local resident I want this plan changed before any cyclists or pedestrians are killed or injured.
"Cyclists and pedestrians cannot safely cross one another's paths in the way envisaged because the numbers are so great at this location. Safety for all is needed, not more customers for A&E."
The London Cycling Campaign, Wheels for Wellbeing and Lambeth Cyclists claim that the hospital has failed to put forward any evidence that the proposed bus stop arrangement would be unsafe.
The three groups said in a joint statement: "We believe that if the trust is successful in mounting a legal challenge to stop the scheme going forward, the likely outcome will be a much-needed safety measure will not be installed and alternative proposals will be unlikely to adequately answer safety issues for pedestrians and those cycling; all to allay fears that have no evidence base."