Ultra has spoken, but Freyberg is watching the sea

Major-General Bernard Freyberg, New Zealand hero of the Great War and Churchill's personal choice, takes command of the Allied forces on Crete on 30 April 1941. He is not delighted: his garrison is a motley assembly of British, New Zealanders and Australians evacuated from Greece, ill-equipped and almost without air cover.

Yet Freyberg has an extraordinary asset. Thanks to Ultra, the breaking of the Luftwaffe codes, the British command knows the German plans for Operation Mercury: a massive airborne assault targeting the airfields of Maleme, Rethymno and Heraklion. On 6 May, Ultra gives the targets; on the 15th, the date is fixed for the 19th, then the 20th.

But the intelligence is passed to him disguised as the report of a spy in Athens, so as never to betray its source. And the doctrine of the day held that an island was taken from the sea: none had yet fallen to paratroopers alone. Freyberg must therefore weigh the precision of intelligence he cannot fully act upon against a seaborne threat that all his officer's experience teaches him to fear.

On the morning of 20 May, as the first Junkers approach, everything rests on the distribution of his meagre reserves.