The impossibility of keeping Englishmen sober ashore was a constant source of complaint, It was the great weakness of 16th century English infantrymen, whose performance when sober was admired even by the Spaniards. Already it was true, as it was to be for centuries, that many saw and despised the drunken sailor ashore, but few knew and admired him at his work afloat.

'A Naval History of Britain' which begins in the 7th century has to explain what it means by Britain. My meaning is simply the British Isles as a whole, but not any particular nation or state or our own day... 'Britain' is not a perfect word for this purpose, but 'Britain and Ireland' would be both cumbersome and misleading, implying an equality of treatment which is not possible. Ireland and the Irish figure often in this book, but Irish naval history, in the sense of the history of Irish fleets, is largely a history of what might have been rather than what actually happened.

It is well known that we fight in God's cause... but unless God helps us by a miracle the English, who have faster and handier ships than ours, and many more long-range guns, and who know their advantage just as well as we do, will never close with us at all, but stand aloof and knock us to pieces with their culverins, without our being able to do them any serious hurt. So we are sailing against England in the confident hope of a miracle.

Whether in peaceful trade or warlike attack, the sea unites more than it divides. Even if it were possible to treat England, or the British Isles, as a single, homogenous, united nation, it would still be impossible to write its naval history without reference to the histories of the other nations, near and far, with which the sea has connected it.

Its subject is the slow and erratic process by which the peoples of the British Isles learnt - and then for long periods forgot - about the 'Safeguard of the Sea', as the 15th century phrase had it, meaning the use of the sea for national defence, and the defence of those who used the sea.

The arrival of the Barbary pirates radically changed English attitudes. Instead of patriotic pirates plundering foreign cargoes and bringing them homes to enrich their countrymen, the 'Turks' were in the usual Mediterranean business of slave-raiding - and now the English were the victims. The West Country men suffered the heaviest, and did not appreciate the irony. The Newfoundland fishery, dominated by Devon ports, lost at least 20 ships in 1611 alone.

In every age states of varying size and constitution and at every level of development have found naval warfare to be one of their most formidable and expensive tasks. Ships have always been large, costly and complicated, and warships much more complicated and costly than any others. Scholars are nowadays inclined to emphasize the power, wealth and sophistication of the Anglo-Saxon kingdoms, and there is not more striking illustration of this than the advanced and elaborate administrative structures of the early English navy.