Hitler wasn't kidding when he threatened to invade Britain - and now staff at Oxford's Bodleian Library have unearthed the documents to prove it.

Oxford and Abingdon were among Hitler's targets in the Germans' invasion plans for the British Isles, according to German Invasion Plans for the British Isles, 1940, a new book out this week.

Last year, the Oxford University library scored a massive publishing hit with its Instructions to Servicemen series.

Instructions for American Servicemen in Britain, 1942 sold 29,000 copies, while Instructions for British Servicemen in France, 1944 sold 24,000 copies.

Now staff at the Bodleian have dug deep into their archives to reproduce the historic Nazi invasion plans.

Bodleian Library spokesman Oana Romocea said: "It's thought Hitler was never intent on bombing Oxford because he wanted to make it the new capital of his new kingdom.

"Oxford is featured in the documents which were used as the basis for this new book.

"A lot of research was carried out by the Germans in the 1930s and some of that information appeared in these documents, which were used by Hitler's generals to compile the invasion plan called Operation Sea Lion.

"The library has one of the few copies of the documents to survive and we want to make our archives available to the public."

The invasion guide is based on three portfolios compiled by German researchers to give an invading army the crucial information it would need about the UK, including guidance on the road system, the geography of different regions, a key to money, weights and measures and translation of Welsh words.

A map of Oxford is included in one of the portfolios, together with a black-and-white photograph of the bridge over the Thames in Abingdon.

Dot Little, the graphic designer for the book, added: "The documents are very well ordered and provide an overall evaluation of the terrain - it's very German.

"The documents were seized by Allied forces as they invaded Berlin in the last days of the Third Reich."

Ms Romocea, a spokesman for the Bodleian Library, said the new book, which is now on sale, and a second title, Instructions for British Servicemen in Germany, 1944, should sell very well.

She added: "There are pre-orders of almost 5,000 for the German Invasion Plans and almost 4,000 for the other book."

*The German Invasion Plans book costs £5.99 while the other book is on sale at £4.99.

HITLER'S PLAN Operation Sea Lion was a World War II Nazi German plan to invade the United Kingdom, beginning in 1940.

The operation was abandoned in September, 1940 and the Nazis only got as far as the Channel Islands.

Following swift victory in the Battle of France, Germany believed the war in the west could be easily won.

The Oberkommando des Heeres originally planned an invasion on a vast scale, extending along most of the English Channel, from Dorset to Kent.

Final plans were more modest, calling for nine divisions to land by sea with around 67,000 men in the first echelon and an airborne division to support them.

The battle plan called for German forces to be launched from Cherbourg to Lyme Regis, Le Havre to Ventnor and Brighton, Boulogne to Eastbourne, Calais to Folkestone, and Dunkirk and Ostend to Ramsgate.

German paratroopers would land near Brighton and Dover. German forces would secure England up to the 52nd parallel (as far north as Northampton), anticipating that the rest of the United Kingdom would then surrender.

The main difficulty for Germany was the small size of its navy. Control of the skies was also unavailable, and on September 17, 1940, Hitler ordered the cancellation of the operation.

Useful phrases for invading forces Wo ist der nachste Tank? (Where is the next tank?) Wo konnen wir schlafen? (Where can we sleep?) Wo kann ich etwas zu essen bekommen? (Where can I get something to eat?) Wo ist das nachste Brucke? (Where is the next bridge?) Wo sind die Kasernen? (Where are the barracks?)