Police are digging up an area of wasteland in a search for priceless treasure stolen in a raid on a castle.

Officers have taped off a property in Alvescot Road near Carterton believing it may contain historical items burgled from Arundel Castle in Sussex.

The collection, valued at more than £1m, was stolen in a raid on the night of Friday 21 May of this year.

The search follows the issuing of eight search warrants at addresses in Oxfordshire as well as Worcestershire and Gloucestershire.

Items included rosary beads used by Mary Queen of Scots, seven gold and silver-gilt coronation cups (for George II, George III, George IV, William IV, George V, George VI and Elizabeth II); two gold batons and other miscellaneous items including 10 silver-gilt Apostle spoons, a silver-gilt casket with hunting and fishing scenes, and a silver-gilt mug.

The property was formerly known as The Ark and had previously been occupied by a roofing contractor.

A 45-year-old man was arrested at an address in Eckington, Worcestershire, this morning by Sussex Police officers in a joint operation with Gloucestershire Constabulary, West Mercia Police and Thames Valley Police.

Specialist search officers from Sussex Police and detection equipment have been deployed as part of the operation which continues.

Six other men who were also arrested are being interviewed by Gloucestershire and West Mercia officers in relation to alleged burglary, assault and drugs offences, all unrelated to the burglary .

Insurers have offered a substantial reward should any of the property be recovered intact.

In June, Sussex Police released photos of two ladders used by thieves to break into the castle.

The two metal ladders, one six-foot long and one 12 foot, but both capable of being extended to twice their lengths, were found there and had been used by the thieves to gain access to the dining room where a window was forced to gain entry.

The ladders had clearly been well used over some years. The long ladder has some distinctive black and yellow paint splashings and each has some worn labelling.

Police hope that someone in the decorating or building trade, or maybe someone who just had them at home, will realise that they are missing them, and will get in touch.

Detective Inspector Alan Pack of Sussex Police said; "Our investigation into the Arundel Castle burglary remains live and this action marks a significant step in our enquiries.

"I would encourage anyone with further information about this burglary to contact us, and also remind people that the insurers have offered a substantial reward should any of the property be recovered intact.

“You can also contact us either online or by calling 101, quoting Operation Deuce.

He added: “We are very grateful for the co-operation of West Mercia, Gloucestershire and Thames Valley Police whose assistance demonstrates how together we will take action to seek to disrupt criminality of all kinds."

In June a reward was offered on the basis that any items stolen were returned in their original, undamaged, condition.