A prestigious charity which helps fund Birmingham's museums has accused civic leaders of undermining the city's cultural heritage through "discourteous negligence".

In a scathing letter, the Friends of Birmingham Museums & Art Gallery criticise the ruling Conservative-Liberal Democrat coalition for tarnishing the city's name through its management of the museums service.

The letter was sent by the Friends' chairman, Dr Ted Hiscock, to council leader Mike Whitby and copied to all city councillors.

In it, Dr Hiscock writes: "This charitable organisation works extremely hard to support and boost the activities of the Museum and Art Gallery and it is a unanimous feeling in this, its 75th year, when members reflect on the

#750,000 of purchases over the years donated to the city, that the support from the council of late has an air of discourteous negligence, which is undermining the staffing, the very foundation of the museums and ultimately the good name of Birmingham around the country and abroad."

It complains that almost two years have elapsed since the departure of former head of museums, Graham Allen, with no sign of a permanent replacement.

The role is currently filled in an acting capacity by the former head of community museums, Rita McLean.

The letter says: "The Friends of the BMAG feel extremely strongly that the future of this element of Birmingham's heritage is being down-valued with the message that its function and contents are low on the list of the current administration's priorities."

The letter represents an unprecedented breakdown in confidence between the Friends organisation and city politicians.

The charity, which is celebrating its 75th anniversary this year and will host a visit from the Duke of Gloucester next month, is a voluntary group whose members raise funds to support exhibitions, displays and new acquisitions.

Over the years it has played a leading role in campaigns such as those which led to the acquisition of paintings by Bellini and Canaletto in the 1970s, and it recently made its single largest contribution, of #10,000, to help buy a major sculpture by the Brazilian-born artist Ana Maria Pacheco.

Last night Dr Hiscock told The Birmingham Post that the letter had been seen and approved by all members of the Friends committee.

"I have written on behalf of the committee but there was 100 per cent support," he said.

"We are concerned that the city appears to be dragging its feet over the appointment of staff. Another concern we have is that a lot of these museum posts are being devalued.

"They are trying to cut costs and making them less attractive, and a number of senior staff have left. If you compare Birmingham to Manchester or Liverpool, I don't know why Birmingham is such a parochial city.

"They say they are the second city but they don't seem to have a cosmopolitan view.

"We feel that as Friends of the museum we contribute on average #25-30,000 a year towards new acquisitions. We are supportive but we feel Birmingham City Council needs to be supportive as well."

A council spokeswoman rejected the criticisms and pointed to prestigious exhibitions being held this spring, including the Toulouse Lautrec display, which opens this weekend.

She said "consistent investment" in the Museum and Heritage Service has created "one of the UK's premier services" which spearheads a regional museums hub 'Renaissance in the Regions'.

The spokeswoman added: "Cultural services continues to be of great importance to the people of Birmingham and to the city council. The city council is considering the optimum position for Cultural Services in its new structures.

"In the meantime the city council has ensured continuity of leadership and delivery by maintaining the service under the leadership of the strategic director who has been responsible for cultural services for the last two years."