The Scottish island weathermen who changed the course of D-Day

The gallant efforts of RAF 518 Squadron based at Tiree were to have such a profound effect on the passage of war their readings led to D-Day being postponed by 24 hours. The decision set the foundation for the success of Operation Overlord on June 6, 1944.

A full moon, low tide, light cloud cover and light winds were required for the assault to have any success. Originally, the first landings were scheduled for June 5, but information gathered by the Tiree crews on June 1 on a flight towards Iceland confirmed two developing areas of low pressure.

The following day a ten-hour flight in the “worst possible weather” contributed to a change in plan for the biggest amphibious assault in military history, which was then postponed for 24 hours.

Behind that decision was a call made by Group Captain James Stagg, of Dalkeith, the “dour” Met Office meteorologist commissioned to advise allied group commanders, led by General Eisenhower, on weather conditions.

An account from Oscar Gill, a meteorological observer with 518 who was on that decisive flight, was published in When Tiree Held the Key to D-Day by John Robertson.

He wrote: “On 2 June 1944, we encountered some of the worst possible weather and I was buffeted about in the nose of the Halifax, for about ten hours gathering quite a few bruises in the process.

"Wilf, the pilot, had to hang on in person for the whole trip as the auto-pilot could not cope. The state of the sea in that depression is very hard to describe and I can liken it to a large pan of jam at full rolling boil on the stove.

“The waves were some 50-60 feet high and going in no particular direction, just bouncing up and down. The wind was lifting spray hundreds of feet into the air and the Perspex nose was splattered all over with salt water.”

Three teams of meteorologists from US, Norway and Britain analysed the readings under the leadership of Group Captain Stagg, who, following some disagreement from the group, made the recommendation the operation should be postponed. On his advice, General Eisenhower, at 4.15am on June 4, agreed.

Later that day, following further advice from Stagg, a graduate of Edinburgh University who later served as a science master at George Heriot’s, Eisenhower moved D-Day to June 6.

A further one-off extended session by 518 squadron departed at 4.55am that morning – just as the first landings were being made in Normandy. The journey was made through violent storms, with waves so high they caused the propellers of the Halifax to bend.

Dr John Holliday, a retired GP on Tiree who founded the island museum and archive An Iodhlann, said 518 squadron had the “most arduous task”, with their efforts having a direct impact on the course of D-Day.

He said: “518 Squadron wasn’t the only Meteorological reconnaissance squadron, but it has got the most attention just given the extremely difficult task it faced.”

Ultimately, there were 28 aircraft based on Tiree with 28 crews of eight men drawn from allied nations. The island, with a population of 1,000 in 1939, was transformed during wartime as it swelled with servicemen as the airport expanded, the RAF base was built and thousands of Nissen Huts appeared.

Dr Holliday said: “It was a big old crew and they took off day and night, so there was always an aircraft in the air. They had an eight to ten-hour flight out into the Atlantic. There were two routes, two triangualr routes, and the northern one pretty much reached Iceland.

"Whatever the weather, they just went up and it was horrific – the beating that the planes got. Many of them never came back.

"The attrition rate from the planes breaking down in the mid Atlantic was high. A lot of people died. They weren’t in combat, although sometimes they could be fired at by U-boats, but they were combatting theses dark and tremendous storms. They never, ever stopped and they went up and down up and down measuring temperature and pressure.

"They flew down to within 100 foot of the sea and up to 20,000 feet and down again – and doing that in the dark when you are using your radio when the waves were 50 to 60ft high. I mean quite often they came back with seaweed on their wings as they were flying so low.

"It was incredibly cold, dangerous, scary and the skill of the navigators and the pilots was amazing.”

The central part of the island was requisitioned by the Ministry of War in 1939, with three runways, a pigeon loft, gas training chamber, gym and hospital then built.

Dr Holliday said: “When 518 came here from Stornoway in 1943, that was when Tiree’s war really started There was a very active social life and a busy little town was set up in the middle of the island. It was very cosmopolitan.

“All of a sudden there were modern roads. There were lorries going back and forward, there was films in the NAAFI, there was pop for kids to drinks and lots of exciting and glamourous young men.

"It had a terrific social effect. It really brought the island up to date fairly quickly. There was a very sudden cultural change on the island. It is mostly remembered with great fondness by the people on the island. Quite a common saying here was the best councillor Tiree ever had was Hitler.”