The Tour de France launch in England later this year could face a £2.3 million shortfall after an internal review revealed organisers had failed to correctly estimate the cost of the event.
The document looks at the contract - eventually given to the Manchester firm WRG - to provide barriers, communications, first aid and other services to the public.
But WRG quoted £4.5m for the bid - more than the original budget of £2.3m. This figure was already reduced by £900,000 from an original bid of £5.4m.
"The estimate did not fully understand the scope of the event and therefore the quantity of resources has significantly increased," the report states.
"It did not take into account the requirement to transport resources around Yorkshire, Derbyshire and Rochdale, and due to the distances and rural locations involved the rates have increased."
The total budget of the three day 2014 Grand Départ from Leeds to London beginning on July 5 is £27m, from a pot of combined funding from local authorities in Yorkshire, Transport for London and central government, via the Department for Media, Culture and Sport.
Organisers have said that this includes £2m to cover unforeseen circumstance
The report, available on the Leeds City Council website, was prepared by Leeds City Council and TdF Hub 2014 Ltd, the company set up to coordinate the TdF in England.
TdF Hub’s chair Sir Rodney Walker, told the BBC he could "absolutely guarantee" the total amount of the WRG contract would not be £4.5m, as it was a worst-case scenario figure and savings had already been identified.
"We're confident we're going to deliver not only the largest event Yorkshire has ever staged, but we're going to deliver it on budget," he said.
"This is a free event that could attract three million people for the two Yorkshire stages alone - I challenge you to find better value for money than that."
Helen Grant, Sport and Tourism Minister, said: "The government is right behind the Tour de France in the UK and is investing up to £10m to help stage the biggest road race in the world.
"I am sure spectators will come out in force to watch the action and I am pleased plans are on track to deliver a fantastic Yorkshire Grand Depart and third stage from Cambridge to London."
Late last year we reported how the simmering dispute between Whitehall and Yorkshire over the Tour de France Grand Départ bubbled up again when sports minister Hugh Robertson described the lack of detailed costing of policing for the event as “pretty extraordinary”.
In an answer to a parliamentary question, Mr Robertson said that the £10 million the government has pledged toward the cost of hosting the Tour did not include policing costs, which were to be met from the £11 million that will be raised by Yorkshire.
He added: “I just say to my hon. Friend, as a gentle point of reference, that if there is controversy about this matter now—I do not know whether there is in Yorkshire—it is pretty extraordinary to have bid for an event without working out how the security is to be paid for.”
North Yorkshire Police and Crime Commissioner Julia Mulligan had written to Gary Verity, chief executive of tourism agency Welcome to Yorkshire to complain that a “lack of clarity” over policing costs had put North Yorkshire Police in a “very difficult position”. She said the force could have to find half a million pounds to cover the difference between the estimated and actual costs.
Sixty percent of the route of the first two days of the race passes through North Yorkshire, leaving the region’s force bearing the “largest part” of policing costs, Mrs Mulligan said.
<p>After an unpromising start, having to be bribed by her parents to learn to ride without stabilisers, Sarah became rather keener on cycling in her university years, and was eventually persuaded to upgrade to proper road cycling by the prospect of a shiny red Italian bike, which she promptly destroyed by trapping a pair of knickers in the rear derailleur. Sarah writes about about cycling every weekend on road.cc.</p>