A 14th century manuscript containing what is believed to be the oldest surviving account of the legends of King Arthur is to be sold for up to £2 million, it was announced today.

The Rochefoucauld Grail, a colourful, illustrated account of the knights of the round table is said to be one of the finest medieval texts in private hands.

It is due to be sold by auction house Sotheby's in London for a price estimated between £1.5 million and £2 million....