Inspector Bruce Thomson said officers searching in the areas around Leuchars and Guardbridge were showing photographs of both the missing people to residents and business owners.

RAF Leuchars Mountain Rescue Team, the Search and Rescue Dog Association and the Coastguard were helping police check the area around the Eden estuary.

The inspector said the teams are based at the car park at the former paper mill and will be checking between the high and low water marks around the estuary and will also be covering areas of open ground.

Searches have already taken place in and around RAF Leuchars airbase.

At Leuchars, police have also set up a base in the car park by the Ye Olde Hotel.

The son of George Patrick has issued a strong appeal, particularly to hotel or B&B owners, to be on the lookout for his father, who has not been seen since last Thursday.

Joe Patrick said his father, a diabetic, needs to take insulin, and the family has no idea how much he has with him.

Joe, who has flown from his home in France to be with the family during the search, said everyone is desperately worried about George.

“The last confirmed sighting of him was at St Michaels Crossroads on Thursday around noon, and this was from CCTV footage on a bus which drove past him as he stood by the roadside.

“From that spot he could have taken a bus to a number of places.

“He used to work as a chief technician at RAF Leuchars, so he knows the area well. If he is in a bed and breakfast, a chalet or caravan park, or a small hotel somewhere, people will not know that he is actually missing.

“I would appeal to owners of accommodation to look out for him, and contact police immediately.”

Joe said he had been out with his sister Pauline to distribute posters with photographs of his father, but time was passing and everyone was becoming more concerned.

When last seen, George was wearing a red winter hip length jacket, with a blue stripe down each arm, and grey trousers. He was also carrying a white plastic carrier bag.

Efforts are also continuing in the search for Ann Robb, who has not been seen since she left her house in the Leuchars area to attend a church service on Sunday.

Ann has been described by police as 5ft 4in, of average build with short grey hair.

At the time she was wearing a blue headscarf, a dark pink three-quarter length anorak with hood, black trousers, dark brown shoes and carrying a dark grey canvas shopping bag. Ann never arrived at St Athernase Church and the last confirmed sighting of her was at 2 pm on Sunday at Guardbridge as she got off a bus.

Mrs Robb’s family, who were at her home in Norman View where she lives with son Richard, declined to speak to the Press today but a neighbour told how police had been knocking on doors on Sunday night.

Another woman in the street, who did not wish to be named, said, “I know Ann to speak to but haven’t seen her since before Christmas.

“She’s a very quiet person. I was shocked when I found out it was her that had gone missing.”

Local community council chairman Caroll Finnie said residents had been checking their property in case Mrs Robb had taken shelter there.

She added, “There is a police interview van in the village and people have been going in there.”

Church elder and community councillor Joyce Edmonston said Mrs Robb was a regular churchgoer but she said, “I hadn’t seen her there the last couple of weeks.”

At St Michaels, residents described the police activity, which had included searches at St Michaels Inn and St Michaels Golf Club.

Heather Foggo said, “Police were here on Sunday going around all the doors asking if we had seen anything.

“I heard from a neighbour that police sniffer dogs and RAF sniffer dogs were being used in St Michael’s Woods.”

Jim Sneddon said, “There was quite a bit of police activity on Friday night and I saw about 12 police officers at St Michaels Inn.

“They were here the whole day searching in St Michael’s woods and in the area.

“They came to my door asking if we had seen him but we have seen nothing. The woods are popular for dog walkers. I regularly walk my dog in there and because it is so well used I think people would notice if anything was out of place.”

Police have asked the public to be vigilant and to look out for both missing people.

Any person who has had any sightings are asked to contact Fife Police on their appeals line 01592 251111.