Professor Ann Sumner was appointed at the beginning of May with the remit of taking the helm after a decision to move the city’s museums from council control to an independent charitable trust.

Chamberlain News understands that Professor Sumner cited “personal and family reasons” in her resignation letter.

The decision will be a blow to Birmingham Museums Trust since Professor Sumner was regarded as one of the leading experts in the public arts field.

In setting up the trust the city council hoped to inject much needed finance into Birmingham’s museums, largely through business rates relief on buildings occupied by a charity. Funding for the trust was also approved by the Arts Council.

Birmingham City Council claimed that, with 1.1 million visitors a year between them, the combined attractions would rank alongside the Guggenheim museum in New York and Oxford’s Ashmolean on the global list of most popular museums.

Former Birmingham cabinet culture member Martin Mullaney, who helped oversee formation of the trust, said Professor Sumner’s departure was a surprise. Mr Mullaney added: “It is a blow, no doubt about it. She was very, very highly regarded in her field.”

Professor Sumner was director of the Barber Institute of Fine Arts at the University of Birmingham before taking the job at the new trust.

She said at the time: “This is a key moment for the city and the wider region, and I look forward to working with the Trust team and building on their recent successes.”

Professor Sumner studied History of Art at the Courtauld Institute, University of London, and undertook her PhD in History at Newnham College, University of Cambridge.

She began her career at the National Portrait Gallery, London and has held curatorial positions at the Whitworth Art Gallery, University of Manchester, Dulwich Picture Gallery, Harewood House Trust, and the Holburne Museum, Bath.

Prior to her appointment to the Barber Institute in October 2007, she had been Head of Fine Art at Amgueddfa Cymru – Museum Wales, for seven years.