Costs of the investigation into RAF gunner Corrie McKeague's disappearance have topped £1m, police have said.

Mr McKeague, from Dunfermline in Fife, vanished after a night out with friends on September 24 last year in Bury St Edmunds, Suffolk.

A wide-ranging search for the 23-year-old failed to find him. Last month, police began to dig through a huge landfill site in Milton, Cambridgeshire.

Suffolk Police also revealed their officers have searched through 3,000 tonnes of rubbish at the site as they searched for Mr McKeague.

The £1m figure includes £544,250 which was spent over and above staffing costs.

The search at the landfill site could take up to ten weeks to complete, with an area of 920 square metres being combed through by a specialist team.

On Friday, Suffolk Police said the area being searched was expanding.

A spokeswoman for the force said: "As the search has been carried out officers have found material that have indicated they are in the right area - finding waste that was clearly identifiable as being from Bury St Edmunds, and within the right time frame.

"However, towards the edges of the area it has also been noticed that the waste may have naturally shifted from the original deposition area."

She continued: "Throughout the search Corrie has very much been in the forefront of officers' minds.

"Enquiries have been continuing while the search has been going on at Milton, with officers gathering further information about Corrie's lifestyle and background."

Police are expanding the search parameters to take this into account and the search will be continuing as the tenth week of work on site gets underway on Monday.

The last CCTV sighting of Mr McKeague showed him walking from a shop doorway and into a horseshoe-shaped area in Brentgovel Street, with no sign of him emerging.

His mother Nicola Urquhart, a serving Police Scotland officer, has led specialist searches for him.

His father, Martin McKeague, has also made numerous visits to the landfill site.

Speaking to STV News last month, he said: "It's just utterly heartbreaking and I don't wish this on anybody.

"I don't even know where the time has gone, I'm kind of just existing. I'm trying day by day to get through this mess."