Nanny has a secret.
She won't tell you how much she paid for a piece of art.
The piece in question is a sculpture by Conrad Shawcross, called Continuum, which was on display at the Queen's House at the National Maritime Museum in Greenwich.
Shawcross describes his work thus:
"a wooden spring-like structure..
moving through itself in perpetuity...
a conceptual model of the day."
Unfortunately, Nanny won't tell us how much she paid Shawcross for the temporary installation.
This is even more unfortunate because the museum receives £15M per year from us, the taxpayers.
Nanny's trustees have twice turned down a request, under the Freedom of Information Act, to reveal the cost of housing the artwork.
Richard Thomas, the Information Commissioner and guardian of the new Act, also refused to publish the figure.
The commissioner's refusal to disclose the size of the payment is being challenged as a test of Nanny's Freedom of Information regime.
The so called "freedom of information" regime is already in trouble; the Information Commission is struggling to cope with a huge backlog of appeals against refusals by Whitehall, and other bodies, to disclose information to the public.
The case about Continuum is being brought by Matthew Davis, a freelance journalist from Brighton, who lodged a series of requests for information about the prices paid by galleries and museums for contemporary works of art.
Mr Davis intends to represent himself at the tribunal, the members of which are appointed by the Government. He is being opposed not just by the National Maritime Museum, but also by the Department for Culture Media and Sport.
We wish him well.