Goodwood House
Burglars took almost £700,000 worth of valuable items from Goodwood House Ian Stannard

Historic heirlooms and diamonds worth almost £700,000, including a ring given to the mistress of Charles II, have been stolen in a raid at one of Britain's stately homes. Police have appealed for witnesses after burglars broke into 17th-century Goodwood House, near Chichester, in the early hours of 13 January and took more than 40 valuable items.

Lord and Lady March, owners of the Goodwood estate, have been left devastated by the theft of the "irreplaceable" items, police said.

Heirlooms taken include an 1820 diamond tiara worth £400,000, an antique 19th-century diamond necklace worth £200,000 and an emerald intaglio and diamond ring, given to Louise de Keroualle, a mistress of Charles II. Rolex and Girard-Perregaux watches, as well as valuable jewellery, were also taken in the raid.

A 26-year-old man from Hampshire has been arrested in relation to the incident and is currently in custody, but police are appealing for witnesses to come forward.

Goodwood House burglary
A diamond tiara, circa 1820, valued at £400,000 was stolen in the burglary Sussex Police

Detective Inspector Till Sanderson, of Sussex Police, said: "The theft of these beautiful and treasured items has left the victims Lord and Lady March devastated at their loss.

"An intruder broke into the house sometime after midnight on Wednesday (13 January) and took thousands of pounds worth of jewels and watches, many of which are irreplaceable. Forensic teams are working with detectives to investigate the circumstances and we are appealing for anyone who saw any suspicious activity during that night up until 7am or in the previous days to contact us.

"Working with Lord and Lady March we are doing all we can try to trace the stolen treasures, liaising with auction houses, stately homes, dealers and those with specialist knowledge. I am appealing to anyone who may know anything to contact detectives on 101 quoting Operation Forster or alternatively you can call the independent charity Crimestoppers anonymously on 0800 555111 (www.crimestoppers-uk.org)."

Goodwood House burglary
An emerald intaglio and diamond ring, which was given to Louise de Keroualle, mistress of Charles II Sussex Police

The Grade I-listed building is owned by Charles Gordon-Lennox, also known as Lord March. It is home to the Goodwood Motor Circuit, which hosts the annual Festival of Speed, and the Glorious Goodwood horse racing events, which attracts tens of thousands of people including A-list celebrities.

Goodwood House burglary
This gold and seed pearl bangle, valued at £1,000, was also taken. Sussex Police