But the Coram Family has found itself in a bruising clash with the Government, which could see it forced to break up and sell off the family silver - a pound;17 million collection of 18th-century art.

It includes one of the period’s pivotal works, a portrait of its founder Thomas Coram, by Hogarth, as well as a harpsichord belonging to Handel, on which he performed the first London recital of the Messiah in aid of the charity.

But the 150 works have languished behind closed doors for several years, with the charity unable and unwilling to divert money from its ground-breaking childcare work to their upkeep.

The works are central to the history of the charity, set up by the retired sea captain Coram in 1739. They were painted for it by some of its society supporters and were intended for the benefit of children and to raise the foundling hospital’s profile among the great and good.

In what it believed was an ingenious solution, the charity planned to put the works in a separate “foundling’s museum” which would serve as an archive and exhibition of the history of childcare in Britain. Then the proposal fell under the merciless gaze of the Attorney General.

The Government’s chief lawyer argues that the museum would mean the charity had moved into the arts and heritage business - and tied up assets donated to help children to boot.

In reply the Coram Family - formery the Coram Foundation - argues that the museum will raise its profile and that it would sell off the works, on condition they remained in situ, giving the charity valuable income. “We would be able to have our cake and eat it,” says chief executive Gillian Pugh.

The charity has had close ties with Labour in recent years. It hosted shadow cabinet meetings before the party came to power in 1997.

David Blunkett used it to launch flagship initiatives such as SureStart, and Tony Blair unveiled the adoption White Paper there only three months ago.

The charity says the Attorney General’s ruling would force it either to sell off the collection - which would be unlikely to realise its full value at present market rates - or lock the door on it for good.

It could also have implications for works held by other educational bodies, from schools to Oxford colleges, which have been given works of art.

The Coram works were the first public collection of art in Britain, and an inspiration for the Royal Academy. They represent not only a pivotal era in British art, but the early history of the foundation itself - the subject of many is life in the hospital, while the early benefactors are the subjects of the large group of portraits.

“They’re not pictures we picked up in a sale,” says Dr Pugh. “They weren’t given to us as an afterthought. They were painted for us, and that’s what makes it special.

“We’re a modern, innovative charity, but this is where we come from.”