Secret records from the earliest days of the Special Air Service (SAS) carrying out daring attacks behind Nazi lines in north Africa and France have been published in a new book marking the regiment's 70th anniversary.

The tome includes first-hand reports from the special forces unit's disastrous first operation in November 1941, from which only 22 of the 65 soldiers who took part returned.

It also features the succinct orders for an ambitious but unsuccessful mission to "kill, or kidnap and remove to England" German commander Field Marshal Erwin Rommel in France in 1944.

The 600-page book, entitled The SAS War Diary 1941-45, collects rare and previously undisclosed documents detailing how the regiment was born out of fighting against Italian and German forces in the deserts of north Africa during the Second World War.

It goes on to describe the elite unit's role in the invasions of Sicily and Italy, as well as in the D-Day landings in France.

A former SAS soldier began the diary to preserve records and photographs of the regiment's incredible wartime exploits after it was disbanded in 1945 at the end of hostilities.

Its existence remained a secret even within the SAS for 50 years but it has now been expanded and is being made public for the first time.

The lavishly-produced book is being published in a series of limited editions, including one set of 100 copies signed by Sergeant Jimmy Storie, the last surviving veteran who took part in Operation Number One.

Viscount Slim, a former SAS officer and president of the SAS Regimental Association, said: "The SAS War Diary is an icon. The fact that its existence has been a secret for over 50 years - even within the regiment - is incredible.

"I can think of no better way of marking the 70th anniversary of the SAS than allowing it to break cover."