Wandsworth Museum has been saved in the final hour by a £2million rescue package from a charitable foundation funded by a local resident.

The revelation has been hailed as an overwhelming success for campaigners, who have been fighting Wandsworth Council ever since plans to close the museum, West Hill library and Alvering library leaked out in January.

The offer from the Hintze Family Charitable Foundation was made only this morning and announced by Councillor Malcolm Grimston in front of a public gallery full of amazed campaigners at the full council meeting tonight.

Coun Grimston revealed the deal was the culmination of six weeks negotiation with the foundation.

Earlier in the night, petitions bearing almost 20,000 signatures opposing the museum's closure had been submitted.

Under the new agreement, the museum collection would come together with the De Morgan collection in the West Hill library building.

Once Wandsworth Council has vacated the building, and a new independent charitable trust has been set up to manage the collections, the foundation will commit a lump sum of £1million. This will be followed by five annual payments of £200,000.

The Court House, which is currently home to the museum, would still be redeveloped into a new town centre library, to compensate for the closures of West Hill and Alvering libraries.

In his letter to the council, the foundation's chairman, Wandsworth resident Michael Hintze, wrote: "A museum for Wandsworth is vital to the people of the borough and London as a whole. We would like to assist in ensuring that such a resource remains available to all who require it."

Neil Robson, of the Wandsworth Museum Campaign Group, said: "I hope now we can put the dreadful last few weeks behind us. There has been so much damage done to the prestige of Wandsworth. It's now time to move forward."

But campaigners stressed details still needed to be checked, especially regarding the staff redundancies, which are still going ahead.

And everyone concerned accepted that further funding would be needed to secure the museum's long-term future.