[6] If built, it was proposed that the bridge would have been open from 6am to midnight, with closures for the preparation for and holding of up to 12 private commercial events per year to raise funds for its maintenance.

In September 2016, Sadiq Khan, Mayor of London, announced a formal review by Margaret Hodge of the procurement processes in relation to the bridge project and its value for money.

[9] In October 2016, the National Audit Office reported on procurement issues and perceived value for money for that part of the cost of the project which was being met by funds (£30m) from the Department for Transport.

[6] In February 2017, the Charity Commission for England and Wales found the financial management of the trust to be satisfactory, albeit with criticisms as to the trustees' approach.

[10] The subsequent report by Margaret Hodge MP was highly critical of the plan, its procurement, its cost, the risk to public funds, and lack of value for money.

Further, the charity proposed to rent the rooftop of the bridge's South Bank landing podium for commercial purposes on every weekend between May and October.

[32] In November 2015, planning documents for the bridge revealed that public access to the bridge was to be controlled, including the use of the tracking of visitors' mobile phone signals to guard against overcrowding, a video surveillance system and security staff known as "visitor hosts" who would have limited policing powers under a Community Safety Accreditation Scheme, including the right to issue fines.

The rules of the bridge were to prohibit "any exercise other than jogging, playing a musical instrument, taking part in a 'gathering of any kind', giving a speech or address, scattering ashes, releasing a balloon and flying a kite.

[8] In June 2013, the Commissioner of Transport for London, Sir Peter Hendy had stated that the public would meet no more than the "enabling costs" of the project of £4m.

[38] Nevertheless, the financial chief for Transport for London considered the proposed bridge extremely expensive when compared with other crossings on the Thames.

[39] Writing in The Guardian in February 2016, Ian Jack contrasted the £60m taxpayer support for the project with the closure of five Lancashire museums – two of which are nationally important – and 40 libraries.

Jane Duncan, president of the Royal Institute of British Architects requested the project be put on hold pending an investigation of the tendering process for the appointments of Heatherwick Studio and Arup.

[41][42] On 16 February 2016, Walter Menteth of Project Compass CIC,[43] a procurement intelligence service, published a detailed report on the irregularities in the procurement leading to the appointment of Arup Group and Thomas Heatherwick by Transport for London; the report concluded that an independent investigation would be appropriate before the public made any further financial commitment to the project.

Yet there is a small but determined opposition to the project, mostly from Labour, which continues to undermine it.In the 17 months to 31 March 2016, the Garden Bridge Trust spent over £26 million, 80% of which was funded by Transport for London.

[11] Sadiq Khan, who had been elected Mayor of London in May 2016, undertook an investigation of Johnson's decisions in relation to the procurement process for the bridge.

[47] In July 2016, Dan Anderson of Fourth Street[48] published a review of the Garden Bridge's Draft Operations and Maintenance Business Plan.

The halted work would have cost £3m for infrastructure preparation in the Tube station at Temple on the north bank of the Thames so that the bridge structure could be built on its roof.

[51] The additional assurance of the underwriting extension was needed in order for the Garden Bridge Trust to complete and file its statutory accounts, due on 31 July 2016.

[52][53] On 8 August 2016, the National Audit Office formally announced that during Autumn 2016 it was to investigate the Department for Transport's handling of its £30 million grant to the Garden Bridge project.

[56] The figures of increased cost and the reduction in funds raised, together with the longer timescale, were then confirmed by the Garden Bridge Trust.

[11] On 11 October 2016, the National Audit Office reported the results of its inquiries into the £30 million funding provided for the Garden Bridge by the Department for Transport.

The manner in which the funding was provided, by block grant to Transport for London left the Department with limited oversight of its own support to the Garden Bridge Trust.

The pattern of behaviour outlined in this report is one in which the Trust has repeatedly approached the government to release more of its funding for pre-construction activities when it encounters challenges.

The Commission considered that, given the public interest, the trustees could have provided more detail in their annual report about the progress made, given the expenditure incurred and the challenges addressed.

[60][61] The planning application was approved by Lambeth Council (local authority on the south side of the bridge), subject to conditions, in November 2014.

[73] In response to the Hodge report, Mayor of London Sadiq Khan, Johnson's successor, announced on 28 April 2017 that he would not provide a guarantee for the future running costs of the bridge, due to concerns about the project's financial viability.

The BBC London transport correspondent Tom Edwards described the situation as a shambles which was "an embarrassing mess for the capital ... already descend[ing] into finger pointing and a blame game over who is culpable for wasting £46.4m of public money".