The Nazi who planned a UK invasion via the Donegal Gaeltacht

Dr Ludwig Mühlhausen

Dr Ludwig Mühlhausen came to the Donegal Gaeltacht to improve his Irish

A suspected German spy identified a small hamlet in the Donegal Gaeltacht as a possible back door route for a Nazi invasion of the UK.

Nazi professor Dr Ludwig Mühlhausen lived in the tiny Irish hamlet of Teelin in 1937, where he scoped out the potential secret U-Boat submarine base.

Upon returning to Germany, he broadcast Nazi propaganda in Irish from Berlin into Ireland during World War Two.

He later became a decorated SS officer.

Dr Ludwig Mühlhausen's secret life is uncovered in a new BBC Two NI documentary Nazi sa Ghaeltacht.

The BBC's Kevin Magee unearthed a file on Mühlhausen in Dublin

In the documentary, BBC journalist Kevin Magee traces the professor's footsteps back to Berlin and reveals that the German scholar was fast-tracked through the ranks of the Nazi regime because of his unflinching devotion to Adolf Hitler.

He also discovers that one of the first things Mühlhausen did when he found somewhere to stay in Teelin was to hang a large picture of Hitler on his bedroom wall.

While in the south Donegal area, he took many photographs and measured the depth of Teelin Bay by dropping lead weights into the tide, forcing locals to later speculate that he was scouting the place out as a potential landing site for Nazi U-boats.

In the documentary, a file at the Military Archives in Dublin, which the Irish intelligence agencies had compiled on Mühlhausen, is uncovered.

Previously unseen documents are also uncovered in Berlin which reveal his efforts to shape a Nazi plan for the Republic of Ireland.

In the end, with the Nazis defeated and Mühlhausen in a prisoner of war camp, he made one last desperate plea for help to Ireland.

The film was made for BBC Gaeilge by Macha Media, with support from Northern Ireland Screen's Irish Language Broadcast Fund, and was filmed before coronavirus restrictions were imposed.

Nazi sa Ghaeltacht is on this Sunday 26 July on BBC Two Northern Ireland at 22:00 BST.