The world's most glorious monastery, at Monte Cassino in Italy, was destroyed during the second world war because of a mistake by a British junior officer, according to new evidence in a book due out this week.

The officer - translating an intercepted radio message - mistook the German word for abbot for a similar word meaning battalion. His version convinced his superiors this meant a German military unit was using the monastery as its command post, in breach of a Vatican agreement which treated it as neutral.

Allied generals ordered a huge bombing attack. Only when the planes were in the air did a British intelligence officer, Colonel David Hunt, recheck the full radio intercept. He found that what it actually said was: "The abbot is with the monks in the monastery".

"Tragically, this was discovered too late," the book says. "The bombers were already approaching."

Monte Cassino - founded in 526 by St Benedict, numbering St Thomas Aquinas among its early monks - was blitzed in what is mourned as probably the greatest single aesthetic disaster of the war. Some 250 men, women and children died.

The ruins created a superb German defensive position which cost thousands of allied soldiers' lives before the monastery fell after a further three months of fighting. Controversy continues over whether it was German-occupied before the bombing.

Hunt's account of the intercept is told for the first time in With Alex at War, the autobiography of Sir Rupert Clarke, aide -de-camp to Field Marshal Lord Alexander of Tunis, deputy supreme allied commander in Europe and the leading British general in the liberation of Italy.

'Awful tragedy'



Last night Brigadier Bryan Watkins, who collaborated with Sir Rupert on the book, said: "It was an awful tragedy. It was idleness by the man who read the intercept. I don't find the story at all hard to believe. War is a balls-up." The book does not name the intelligence officer.

Field Marshal Lord Carver, former chief of general staff, who is writing the Imperial War Museum's official history War in Italy, 1943-45, said he had not previously heard of the intercept.

Col Hunt - Alexander's personal intelligence officer - later became Sir David Hunt, diplomat, author and private secretary to the post-war prime ministers Clement Attlee and Winston Churchill.

In February 1944, when Monte Cassino was bombed, he was general staff officer in charge of intelligence in a unit with Sir Rupert. German strongpoints in the mountains around Cassino were imperilling the allied advance towards Rome.

Fighting in conditions almost as severe as the trenches of the first world war, allied units on exposed slopes were under heavy artillery fire which they were convinced was being directed by spotters in the 1,600ft high monastery. But Sir Rupert's book says Hunt told him after the war that the monastery was not occupied by the German parachutists who were holding the Cassino feature.

"However, a radio intercept of the German command net reported that a parachute commander had been heard to ask 'Ist Abt in Kloster?' and was answered, 'Ja in Kloster mit Monchen'.

"The intelligence officer who received the intercept only recorded the answer 'Yes from the enemy'. The translation then produced was 'Is the HQ in the abbey?' - the word 'abt' being taken as an abbreviation for 'Abteilung' (a battalion) rather than abbot. It was only when Col Hunt questioned the translation and the whole intercept that it transpired that the correct reply to the question was, in fact, 'Ja, Abt is mit Monchem in Kloster'. ie: 'Yes. The abbot is with the monks in the monastery'."

Sir Rupert adds: "Rather than saving lives, that bombing would lead to savage losses".

From his own study of the papers of British, American and Commonwealth generals in the Imperial War Museum, Lord Carver said he did not think the reportedly misread intercept was likely to have influenced the decision to bomb.

"What they were arguing about with each other was not whether the monastery was occupied but whether, if the attack was going to be successful, the top of the hill should be obliterated."

He added: "I don't think the bombing was necessary or could be justified."

But Brigadier Watkins said: "Both the allied and German sides had given undertakings to the Pope that they would not destroy the monastery. We know from records that Alexander was very conscious of allied responsibilities under this agreement.The intercept, in its mistranslated form, implied the Germans had broken their word. That exonerated the allies and served as a green light for the bombing."

In public, allied leaders exploited the belief that Monte Cassino was occupied to prepare opinion for aerial attacks on it. On February 11 - four days before the bombing - the Daily Mail ran an army-inspired lead story, Nazis Turn Cassino Monastery into Fort.

On February 14 allied guns fired leaflets over the area warning that, in view of the German occupation, "with very heavy hearts we are going to have to turn our weapons on the abbey".

The abbot, who survived the bombing, said: "I swear there were never any German soldiers in the area of the monastery."

Panzer corps messages quoted by German historians after the war speak of a 300-metre military no-go area around the abbey. But details about the timing of these messages are not clear enough to rule out the possibility that they were transmitted as propaganda after the bombing.

Monte Cassino, restored in the 1950s, is a shrine for relatives of the estimated 183,000 soldiers on all sides who lost their lives in the battles around it.

From Lombards to Second World War

529 St Benedict founds the monastery, with a routine of prayer and farming, on a pagan temple site 87 miles south-east of Rome. There he writes the Rule of St Benedict, which becomes a guide for celibate asceticism. Monte Cassino becomes the font of western monasticism

547 St Benedict dies

580s Lombard forces storm the monastery. Its copy of the Rule is taken to Rome for safety

884 Saracen forces storm the monastery

1030 Norman forces storm the monastery

1066 New bronze doors for the abbey are cast in Constantinople (now Istanbul) for the abbot Desiderius

1087 A scholarly monk, Constantine the African, dies after giving western civilisation its first systematic account of classical Greek medicine through translations

1230 Thomas Aquino joins Monte Cassino for spiritual instruction. He becomes theologian St Thomas Aquinas

1349 Earthquake damages buildings

1500 - 1600 Buildings repaired and extended

Late 1943 - early 1944 The town of Cassino becomes a key German defence point against the allied advance on Rome

February 14 1944 Allied artillery fire leaflets alleging German occupation of the monastery and warning of bombing

February 15 Allied bombers obliterate the monastery

1950 -1960 Monte Cassino is rebuilt after an international appeal. Virtually all its decorative detail had been destroyed; but the bronze doors were found and restored to their place