London Assembly members have called on the Mayor to ensure taxpayers have access to the Garden Bridge “in perpetuity” in return for part funding the scheme.

Taxpayers were initially due to make “a small investment” of £4m to cover planning and feasibility studies, with the scheme’s expected £160m bill being met by private and commercial donations.

However Mayor Boris Johnson subsequently changed his mind and ordered TfL to provide £30m with the UK Government pledging to provide a further £30m.

Last month it emerged that taxpayers will have no guaranteed access to the bridge, despite paying more than a third of its costs.

There’ll also be a ban on cycling and larger groups will require permission to use it.

Members of the Assembly’s Budget and Performance Committee say Mr Johnson should have placed conditions on his funding, including ensuring the public’s right of access.

In a report published today, the committee says “we recognise that there is an arguable transport case for TfL’s funding for the bridge” and says early signs are that “it will provide a good return on investment.”

However AMs say the Mayor should set out publicly the circumstances in which he’d agree to further increase taxpayer backing if organisers are unable to secure other donations or costs rise.

They also express concerns about “a lack of transparency” surrounding the project and say the Mayor should have leveraged his financial support to ensure the public can better scrutinise it.

Committee chair John Biggs AM said; “The Garden Bridge is a controversial proposal, and its details need to be properly ironed out.

“The Mayor agreed to provide £30 million from TfL’s budget to help get it built and, in return TfL needs to ensure that the public’s access rights are guaranteed.

“The Mayor also needs to ensure that the cost to the taxpayer won’t be increased without very careful consideration.”