A set of carved ivory busts featuring Keighley's first MP - Sir Isaac Holden - and his family is to be auctioned at Sotheby's.

The six sculptures, which are from a private collection, date from around 1870.

Auction house bosses anticipate strong interest in the lot - expected to fetch between £500 and £700 - when it comes under the hammer this month.

The set depicts Sir Isaac, his wife Sarah and duplicate busts of two of his four children.

A Sotheby's spokesman said: "The sculptures came to us as part of a consignment from a private collection.

"They are not signed so we do not know who carved them, but the pieces are of lovely quality and are clearly the work of a very good mid-Victorian sculptor.

"It is a mystery why the set features just two of the children, and why duplicates were produced of those two. Unfortunately little is known about the origins of the work."

Sir Isaac - born into humble surroundings near Paisley in Scotland - was a textile magnate who founded the world's largest wool-combing establishment in Bradford.

He was also a Wesleyan, an inventor and in 1885, aged 78, became Keighley's first MP, a post he held for 11 years.

He was behind the construction of the palatial Oakworth Hall, which remained his home until his death in 1897.