A fire chief undercharged Cheltenham racecourse for giving fire support in return for its festival hospitality, it has been alleged.
A Freedom of Information request revealed Gloucestershire Fire and Rescue Service charged varying amounts while Stewart Edgar was chief officer.
Gloucestershire County Council, which oversees the fire service, said the matter had been referred to the police.
Mr Edgar and the racecourse have both denied any wrongdoing.
Whistleblowers told the BBC Mr Edgar, who resigned last year, negotiated a cheaper rate for providing the service in return for the use of a hospitality box.
On one occasion the racecourse was not charged anything to provide support at the annual National Hunt festival.
The council said it was a statutory duty for the fire service to work with race organisers “to reduce suffering or harm to animals and riders”.
During the annual festival the service would typically provide eight staff on each of the four days, each covering a 10-hour shift, it added.
Figures obtained through the BBC’s Freedom of Information request showed Cheltenham Racecourse was charged vastly different figures for providing support during the festival when Mr Edgar was in charge.
In March 2015 it paid £10,950, in 2016 it paid £5,460, in 2017 it was not charged and in 2018 it paid £4,550.
The council said on each of these occasions the amount charged was “never sufficient to cover the cost of the crews attending”.
This year, when Mr Edgar was no longer in the role, it was charged £14,960.
Mr Edgar said in a statement he denied any wrongdoing in connection with the allegations, and he “does not accept acting improperly at any time”.
The racecourse said it had “not provided any contra hospitality in exchange for services from Gloucestershire Fire and Rescue or any individual associated with the service”.
A spokesman added: “Any non-payment for services in 2017 will be because we have yet to be invoiced for payment.”
Gloucestershire Constabulary said the matter had been mentioned to it, but no investigation had begun because more information was required.
Last week other allegations concerning Mr Edgar’s conduct while chief fire officer were highlighted in an internal audit.
Mr Edgar resigned last year over the sale of a Land Rover, which he undersold then later bought for himself. A police investigation into that incident is continuing.