Nottinghamshire County County council has paid for 54 non-disclosure orders in the last five years.
Data revealed by the Freedom of Information Act show the council spent £617,822.75 between 2013 and 2017.
Non-disclosure agreements (NDAs) are legal contracts which can be signed for several reasons.
The most common is when an employer is leaving a workplace with commercially-sensitive information they accept a financial settlement on the understanding they will not share the information.
But one opposition party has said the figures are a cause of ‘enormous concern’.
The amount spent by the county council has decreased every year from 2013.
NDAs hit the headlines recently after Lord Hain used Parliamentary privilege to state Sir Philip Green had used NDAs to prevent disclosure of several allegations. The Telegraph had been unable to published details of the allegations due to an injunction. Sir Philip denies any wrongdoing.
Nottinghamshire County Council is currently led by the Conservatives, but was held by Labour between May 2013 and May 2017.
The figures released by the council show the total spent on NDAs in the following years;
2013 – £308,490.61
2014 – £100,423.68
2015 – £77,879.28
2016 – £72,889.86
2017 – £58,139.32
Due to the nature of the agreements, it is not possible to ascertain what is being prevented from disclosure.
Marjorie Toward is the county council’s service director for customers, governance and employees, and said: “The council only uses non-disclosure agreements (NDAs) in exceptional circumstances as a means of mutually agreeing the termination of someone’s employment.
“NDAs can be mutually beneficial to the employer and employee and are used to protect the interests of both. Any such agreement requires the employee to have access to independent legal advice.
“The county council promotes the Whistleblowing Policy to encourage employees to raise serious public interest concerns about any aspect of the Council’s work and does not use NDAs as a way of suppressing claims.”
Jason Zadrozny is the leader of the Ashfield Independent Party, and represents the Ashfields ward.
He said: “These figures are a cause of enormous concern. The secrecy and erosion of transparency that exists around Nottinghamshire County Council is shocking.
“Now we find out that their attempts to stop whistle-blowing has cost a whopping £620,000 over the last five years.
“This is at a time when the council has a budget black hole of £54 million.
“This Council is increasingly carrying out their business behind closed doors. The recent working group on creating one big ‘Super’ Council was a classic example.
“This county council needs reminding who pays for it – the public – through one of the highest council taxes in any shire county in Britain.
“For this reason, the council should strive to be as transparent as possible.
“The hundreds of thousands of pounds of ‘hush’ money they are spending shows that they are doing the opposite.”
Nottinghamshire Labour group declined to comment on the issue.