Top secret German maps showing Adolf Hitler plotted to blow up bridges, factories and power stations across Shropshire were going under the hammer in Ludlow today.

The maps highlight potential targets for Luftwaffe bombers during their devastating raids on Britain in the 1940s , with bridges in Shrewsbury and Ludlow, industrial sites in Telford and the Iron Bridge among those marked with coloured symbols.

Richard Westwood-Brookes, historical document expert at Mullock’s Auctioneers, said the maps were proof the Nazis were keen to attack strategic sites in Shropshire.

He said: “There are these purple symbols across the county clearly showing the bombing targets and it is absolutely chilling to see familiar places on the maps.

“You can see the Iron Bridge, businesses in Wellington and bridges in Shrewsbury and Bridgnorth all in there. It seems they were obviously keen to have a go at the bridges all along the River Severn.

“It was also interesting to see some form of military works in Craven Arms highlighted on the map. I don’t know where or what this was, but it is clearly marked.”

Mr Westwood-Brookes said the secret bombing blueprints were originally discovered by an RAF officer while he was clearing out Hitler’s geographical library at the end of World War Two.

The officer’s family has now given them to Mullock’s to put on sale for the first time. Mr Westwood-Brookes said:

“Although we have known in the past from other documents that Nazis knew a lot about Shropshire and were very well aware of the area, these are still very interesting documents.

“I expect we will be fairly busy for the sale, although increasingly we get many more people bidding over the phone than actually attending the sales in person.”

The Shropshire sites are on a small scale map of what the Nazis called the North Midlands, including Sheffield, Manchester and parts of the Midlands. It is just one of a large collection of maps due to be auctioned from 1pm today at Ludlow Racecourse.

The maps are believed to date from 1942 and show the Nazis’ plans for raids over Britain, known as Operation Sea Lion.

Mr Westwood-Brookes expected the map lots to sell for up to about £200 each but said it was always difficult to assess how bidding would go on the day. A signed first edition copy of Hitler’s book Mein Kampf is expected to reach about £8,000.