Birmingham City Council is spending almost £750,000 a year on mobile phone bills for staff and councillors.
The authority has issued 5,300 phones to staff and council members under a deal with Vodafone.
Figures obtained by The Birmingham Post through the Freedom of Information Act show that between November 2004 and October 2005, the council paid £474,000 in mobile call charges and £230,000 in line rentals.
Almost 20 per cent of the council's non-teaching staff qualify for a phone. They pay for personal calls themselves, but the council was unable to say how much it had recovered for non-business use.
More than 1,000 phones were handed to officials in the education department alone, and 43 to schools.
Housing has 900 phones, social services 670, economic development 262 and highways 247. The planning department has 94 phones and the urban design unit 103.
Most individual bills are less than £100 a quarter.
One unidentified user in the central resources unit ran up a £1,300 bill between August and October 2005.
A spokesman said: "Names of individuals if released separately would not necessarily constitute personal data but the release of names and additional identifying information would constitute personal data and therefore is exempt from disclosure under Section 40 of the Freedom of Information Act."
There was uncertainty about the identity of phone users.
The spokesman added: "The format in which the information you requested is held lists councillors, officers or service areas to whom the mobile phones were originally allocated and this may not necessarily reflect the actual main users in all circumstances."
Other large quarterly bills for a single phone included £711 in social services, £484 in highways and £431 in housing.
Freedom of information officer Christopher Lambeth said the local authority had taken steps to cut costs.
Mr Lambeth added: "Birmingham City Council obtains mobile telephones from Vodafone through a contract negotiated by the Office of Government Commerce. Over the past three years we have seen line rental decrease by over 27 per cent, call charges to other Vodafone mobiles and to land-lines by 33 per cent.
"The Office of Government Commerce is in the process of evaluating tenders for a new contract and we are confident that our mobile phone charges will continue to fall this year."
He said the £474,000 call charges would be cut after personal calls were retrieved.