Southwark's planning committee has agreed to alter the legal agreement for the One Tower Bridge development to prevent tenants of a new block of council housing from being able to use the communal garden available to private residents.

Under the terms of the agreement linked to the original planning permissions for the One Tower Bridge development approved in 2011, residents of the affordable homes built as part of the scheme were to be given the right to access and use the same communal areas as those living in the adjacent homes sold on the open market.

Sales brochures for One Tower Bridge – where homes cost up to £15 million – boast that "residents enjoy exclusive access to an appealing private courtyard garden, consisting of three individually designed areas, each characterised by its own unique water feature, including a dancing fountain, lily pond and stone bubbler fountain.

"The garden is planted with a variety of shrubs and trees including hornbeam, magnolia and multi-stem pine. Granite seating looks onto a formal lawn and lavender has been planted to enhance the tranquil atmosphere."

Now Berkeley Homes has won Southwark Council's backing for a raft of minor amendments to the scheme, including the removal of the right of tenants of Horace Jones House, the City of London Corporation social housing block, to access the shared podium garden.

The developer argued that the cost of providing access for council tenants would push up their already high service charges to unaffordable levels.

In addition, according to planning officers' report to councillors, a loophole in the wording of the original legal agreement means that "Berkeley Homes would be required to subsidise any increase in cost of the affordable housing units resulting from the provision of access to One Tower Bridge facilities which would be unduly onerous".

Simon Bevan, Southwark's director of planning, told councillors that the exclusion of City of London tenants from the podium garden was "not seen as any significant restriction on how they enjoy their property" – especially given that Horace Jones House will have its own roof garden.

Asked by Cllr Sarah King (Labour) why the garden had originally been intended to be shared between private residents and social tenants, Mr Bevan said that "it was an aspiration for a certain amount of flexibility that turned out to be impractical".

In their report to councillors, planning officers noted that: "Given the considerable amount of communal space provision that would still be accessible and convenient to the CoL residents, officers consider that these residents would not be disadvantaged by the proposed restriction of the podium garden and the scheme would continue to meet the policy objectives of securing tenure blind development."

Cllr Adele Morris (Lib Dem) warned that "to the outsider this could look as if this is the private residents being a bit snooty and saying 'we don't really want the Corporation of London tenants using our space'" and wanted reassurance that Horace Jones House residents would stil have access to enough open space to meet all relevant policies.

Berkeley Homes' application was approved unanimously by councillors on Southwark's planning committee.