UK police will be asked to investigate the award of the contract to design the $279m Garden Bridge over the Thames in London to design studio Thomas Heatherwick and consulting engineer Arup.
Opponents of the bridge will submit a complaint to Scotland Yard alleging "malfeasance" – misconduct by a public official – against London mayor Boris Johnson and the Transport for London (TfL) procurement process.
The central allegation is that Heatherwick and Arup had been lined up to win the contracts before tenders were issued.
According to a report in newspaper The Observer, Johnson – who as well as being mayor, and an MP, is the chairman of TfL – met Heatherwick privately before tenders were announced.
TfL broke the law, simple as that, and it is a great shame no other bidder has challenged the decision in the courts– Peter Smith, formerly procurement director for the Department of Social Security
The newspaper reveals that the mayor’s private diaries show that on 1 February 2013 Johnson had a "meeting with Thomas Heatherwick". On 13 February, TfL invited Heatherwick Studio to tender for the project along with two other firms.
Campaigners against the bridge point out that Heatherwick came top in the "relevant design experience" category, even though the firm had designed one other bridge, whereas competitors had designed up to 25.
And despite submitting the highest quote, the bid was judged by TfL as the most "economically advantageous".
Johnson’s handling of the project has been criticised by a former government adviser who delivered a damning assessment of the procurement process to appoint Heatherwick and Arup, although there is no suggestion either firm behaved improperly.
Peter Smith, formerly procurement director for the Department of Social Security, told The Guardian newspaper: "TfL broke the law, simple as that, and it is a great shame no other bidder has challenged the decision in the courts."
The bridge, envisaged as a heavily planted pedestrian crossing, has divided opinion in the capital. Those against it point out that although it is a private sector scheme, about a third of its construction costs are due to come from public funds.
They also argue that the bridge, which would cross the Thames at Temple station, is not needed, as nine bridges span the 3.2 km between Westminster Bridge and London Bridge, seven of which can be crossed by foot.
Proponents of the plan argue that the bridge would add another 3.5 million visitors a year, an 18% increase on 2014 numbers.