Anthony van Dyck's Princess Mary (1631-1660)

One of Charles I's most treasured Van Dyck paintings has been returned to Hampton Court Palace more than 300 years after a royalist fled with it during the English Civil War.

The portrait of the king's daughter, Princess Mary, adorned his chamber wall in the last days of his reign while he was under house arrest at the palace.

But it was saved from the parliamentarians under his express orders when he fled his captors in 1647.

Under the care of Lady Aubigny, an active royalist supporter, the painting was taken to the Netherlands a year later and remained in various continental collections for more than three centuries.

It was not until 1967 that the portrait appeared on the London art market and was bought by Van Dyck expert, Sir Oliver Millar.

The portrait, painted by the Flemish baroque artist Anthony Van Dyck in 1637, has now been re-hung at Hampton Court after it was acquired for the nation.

It was obtained under the Acceptance Lieu Scheme by the Museums, Libraries and Archives Council, on behalf of the Government, which enables items of historic or artistic importance to be given in place of inheritance tax.

Chairman of the MLA, Andrew Motion, said: "This is a very beautiful painting, and a very important part of our historical and cultural heritage; it's wonderful to see it back in Hampton Court Palace, where it once hung, this time to be enjoyed by all."

While under house arrest at the palace, Charles I was allowed his paintings, which were brought down from Whitehall.

When he fled in November 1647, he left a note for the palace's commander, Colonel Edward Whalley, describing the painting as: "the Originall of My Eldest Daughter [which] hangs in this chamber over the board next the Chimney which you must send to my Lady Aubigny."

The portrait, which depicts Princess Mary aged around six, wearing a silver-laced gown and pearl headdress, goes on display at the palace today