Titian's Diana and Actaeon

The public are contributing as much as £500,000 to the campaign to keep Titian's Diana and Actaeon on public display.

The contents of collection boxes in both the National Galleries of Scotland in Edinburgh and the National Gallery in London are expected to reach between £300,000 and £500,000, it was revealed yesterday. The campaign to keep the painting in public hands has now entered its final three weeks.

Both galleries have until December 31 to show they have raised £50m to buy the painting from its owner, the Duke of Sutherland.

The painting has been on loan to Scotland since 1945 as part of the Duke's world-class Bridgewater Collection, which also includes other works by Titian, three paintings by Raphael, a seminal self-portrait by Rembrandt and the Seven Sacraments by Poussin.

The Duke has offered Diana and Actaeon to the NGS and its counterpart in London for £50m as the first part of a deal that will help guarantee that the rest of the works in the Bridgewater Collection remain in public hands for at least another generation, and not be sold on the open market.

If the galleries find the money, they will have until 2012 to find a further £50m to purchase Titian's Diana and Callisto.

Yesterday, John Leighton, the director-general of the National Galleries of Scotland, warned that reports over the weekend that nearly all the money for the first painting had been raised were "inaccurate".

He said that "a lot of different things still have to fall into place in the next few weeks" for the £50m to be reached.

Money from the governments in Holyrood and Westminster has still to be pledged in detail, and the galleries are waiting to confirm contributions from individuals and private trusts.

The campaign also still hopes to raise £2m from private individuals in Scotland, to add to the £10m from the National Heritage Memorial Fund and £1m from the Art Fund that has been publicly pledged.

However, the public response to the campaign has exceeded both galleries' expectations. They had expected to raise around £300,000 from contributions to collection boxes.

Art lovers have donated everything from small change to large cheques, and are also giving money online and through the post.

Mr Leighton said: "It looks like we will exceeding the £300,000 figure in London and Edinburgh and that is obviously very good.

"It is more than we had anticipated. There are cheques coming in every day in the post and that is very encouraging."

If acquired, Diana and Actaeon will be shared on a rotating basis between London and Edinburgh, spending five years at a time in each location.