Operation Jantzen, a rehearsal of D Day was conducted on Pembrokeshire’s beaches in July and August 1943, writes historian Mark Muller in part two of his special articles to mark the 75th anniversary of the Normandy landings.

Part one is here.

Operation Jantzen was deemed to have been considerably less successful than had been hoped for but the operation had been launched to find such weaknesses.

The manoeuvring of fully laden lorries up the steep ramps of vehicle landing craft was found to need more practice.

They needed to be reversed up the ramps which wasn’t something that drivers were used to doing.

When unloading, many of the same lorries were driven off when the landing craft were still in water that was too deep with the result that many of these vehicles were ‘drowned’.

Just these problems alone were sufficient to cause major delays at both ends of the operation.

Additionally, the use for the first time of concrete barges to carry fuel which leaked and sank were found to be totally inappropriate and the unloading of 16,000 tons of supplies was far below the 23,000 tons that had been aimed for.

The construction of the emergency landing strip at Tavernspite in forty eight hours (although not fully complete for four days) might sound impressive but was considered to have taken too long.

One of the main factors which delayed D Day one year later was the weather and during the 1943 rehearsals a severe storm appeared on D Day + 10 which beached several vessels.

From as early as the 1960s and 70s reports began to appear of Churchill, Montgomery and Eisenhower having been present at the exercise.

Additional detail emerged such as Churchill watching the ‘invasion’ whilst seated on the wall of the pub at Wiseman’s Bridge, drinking a cup of tea.

None of this ever appears in any histories of the county or of accounts of Churchill’s movements during this period.

During the 1980s and 90s, as a result of this omission, the late Pembrokeshire historians Dilwyn Miles and Roscoe Howells engaged in exhaustive research to try and establish whether there might be evidence to support Churchill’s presence.

Dilwyn Miles wrote to Churchill’s daughter, The Lady Soames; official Churchill biographer, Dr Martin Gilbert; parliamentary historian, Roland Thorne; the Churchill Archive Centre; The National Archives at Kew Gardens, and a host of others. The original letters and their replies are lodged in the Pembrokeshire Archives in Prendergast and make as much of an ingredient in the whole story as the details of Operation Jantzen.

The replies all suggest that it ‘might’ have happened but that no evidence exits (the presence of Montgomery and Eisenhower having long been discounted).

Against this, are a fair number of, albeit, second hand and second or third generation accounts of Churchill having been there.

A letter existed for years (but only a transcript – the original having disappeared) that was purportedly written by Churchill and sent to the host of the pub thanking the publican for his hospitality and the tea.

Almost immediately that the operation had been completed, Americans arrived in Pembrokeshire.

The whole of the UK became a collection point of troops and supplies in readiness for D Day, and to Pembrokeshire came the US 28th ‘Keystone’ Infantry Division part of the three million American troops that were to swamp the UK.

The Keystone Division was one of the oldest units in the US army and was to become one of the most decorated.

This Division landed in France a few weeks weeks after D Day and marched down the Champs Elysees in Paris on 29 August 1944. They were the first US troops to enter Germany.

In March 1944 the 28th moved out of Wales, closer to embarkation ports as D Day approached, and a second infantry Division was briefly billeted in Pembrokeshire. These, the 2nd ‘Indianhead’ Infantry Division had been training in Ireland since October 1943 and Pembrokeshire was a brief stop en route to their embarkation point.

They landed on Omaha beach on the 7 June; D Day + 1.

Both of these divisions suffered extensive casualties. Operation Jantzen had been a wholly British rehearsal.

When the Americans did their own rehearsal at Slapton Sands (Operation Tiger) in April 1944 it resulted in the deaths of 700 soldiers when eight landing craft crowded with men were attacked and two sunk by German E Boats.