Oxford City Council's revenues and benefits service is struggling to cope with a huge backlog of council tax post because more than half of its assessors have left in the past year.

The department employs 90 staff, but 12 benefit assessors from a full team of 23 have already left in the past year.

Revenues and benefits assessors are responsible for collecting nearly £60m in council tax and distributing £50m in benefits, but they are now weeks behind with their work.

Indeed, things are so bad that managers had considered drafting in agency workers on £30 an hour to help clear the backlog.

The problems at the department mean that:

4,500 items of important council tax correspondence remain unanswered

There is a five-and-a-half week delay in replying to letters against a target of 14 days

The department is overspent by £250,000

It takes staff six days to scan urgent information on to a computer -- where a year ago it took just 36 hours

Half the council's benefits assessors have left the department in the past year

Staff recruitment and retention is having a negative impact on morale

It takes approximately 13 weeks to adequately train new staff.

Revenues and benefits manager Paul Warters, who has been in the post for two years, is trying to instill a culture of "doing things as they should be done rather than as they have always been done" in his staff.

He stressed he was confident the picture would look brighter by the New Year.

He said: "It's fair to say our workload has increased and we have been making pro-active steps to recover money from people.

"People paying council tax will regrettably have a delay in replying to their letters, but we will have that under control by the end of the year.

"I am disturbed by the retention issue, but unclear about the morale issue.

"We are currently advertising for six staff, but are confident that the staff we currently have will get us into a position we are happy with."

The news follows reports that there were a record number of sick days taken by staff in the first quarter of this financial year.

The Town Hall has been under Government orders to improve its council tax collection rate.

The past year has seen its workload increase by 21 per cent as it pursues persistent debtors through the courts.

Last year the authority collected £56m in council tax -- a rate of 95.4 per cent, which was a record, although some £1m is outstanding on bills issued in 2003-04.

The rate at which benefits are paid has also improved, although it is still behind the Government's target of 35 days. Two years ago it took the city council 80 days to pay a benefit claim, while today it takes 38 days.

Liberal Democrat city councillor and finance scrutiny member John Goddard said: "I am concerned that halfway through the year we are heading for a substantial overspend in circumstances that could have been largely foreseen.

"Paul Warters inherited a ghastly situation that he has not managed to turn round yet.

"Morale in the revenues department is appalling and that is reflected in the rate at which people leave and we are running it with inadequately trained staff."

Emma Goodall, the city council's Unison representative, said: "Unison is concerned about the problems with staff retention and the impact this has on workloads and resulting staff stress and morale.

"This is something we will certainly be looking into."