Honoured with your invitation to speak today, conscious that you have chosen one of your own for the task and that we all belong to yesterday and can claim to have done the state some service, I was reminded of an encounter in As You Like It. Orlando meets his father's old servant, Adam:

"O good old man, how well in thee appears
The constant service of the antique world,
When service sweat for duty, not for meed
Thou art not for the fashion of these times ..."

Our Service does indeed now seem to belong to a very distant yesterday and, immodest though it be for me to say so, most of us did put duty before reward. As for the fashion of those times, I recently watched Channel 4's TV drama series Indian Summers [DVD]. Despite being about an empire other than our own and at a time when I was still a toddler, I reflected that while its imagery of alcohol, club, gossip, racism and sex certainly played a part in our lives, my recollection is that we did find time for a few other activities!

Indeed, earlier accounts of empire, however critical, provide a rounder balance: Kipling, Somerset Maugham, E.M. Forster, Paul Scott and Jan Morris's great imperial trilogy. Arthur Grimble's Pattern of Islands even became an 'O' level set book for a decade or more. Alas, in the fashion of these times, Grimble is now a fallen idol. Years after his death he was unfairly castigated in the High Court by the Vice-Chancellor, outraged by a letter written in 1928 in classical Gilbertese, a flowery and poetic language, in which Grimble wrote to the Banabans as their 'long standing friend and father' on a matter of 'life and death'. What sounded over the top in the English of the 1970s in context was really very little different to the convention whereby we all used to sign our letters 'Your humble and obedient servant'. I am sure, too, that I am not the only person in this room to have been called 'father' by those seeking a favour.

What happened to Grimble's reputation indicates the change in public perception that has taken place since generations no longer grow up, as I did, imbued with the glory that was Rome, aggrieved by Latin homework but never by Caesar's conquest, and ready to work in empire without personal qualms or criticism from others.

Disengagement from classical education coincided with disengagement from empire, which led, understandably and for the better, to a less partisan historical assessment. It is said that history is written by the victors and it is good to be reminded that there are two sides to every story. It is to our credit that we are able to look back not only to see our faults but also how we moved on. Just as Britain took the initiative in the abolition of the slave trade, so Britain came to acknowledge that independence should be the end of empire, accepting that nobody wants to be subject to somebody else.

The story of empire, particularly of the empire of settlement, includes bloody conquest, devastating consequences to indigenous populations and exploitation. Bad news makes for the better copy. It was the worst of empire that made headlines, so dominating the teaching of its history, the writing of novels and the making of films. We should not be surprised that it is associated with guilt, shame and often the ridicule of those who worked in it.

But empire is not the original sin of Britain. As John Darwin, with great authority, has made clear, empire is the default system of human governance. We too readily forget that the Russian empire, both Tsarist and communist, was expanding contemporaneously with the European empires. The Chinese, Mughal and Ottoman empires had earlier origins. There were other smaller but powerful empires in Africa and elsewhere. The American informal empire may be a less obvious latecomer, but it has been one of the most significant in terms of influence and culture, such is its power base. The movement of people, goods and ideas has been the norm since mankind first outgrew Eden. What we were doing was not unique, and if we had not done it somebody else almost certainly would have.

It is also the fashion of these times to look for people to blame, and our Service is a convenient whipping boy. Recalling that Jack Straw, as Foreign Secretary, once remarked that most of the problems that crossed his desk had been caused by us, I have been half expecting that somebody would blame us for the emergence of tax havens, now in the doghouse, because the Bahamas, Caymans, Turks and Caicos are among their number!

It is hurtful to be blamed and to be expected to feel guilt for doing a job we enjoyed, that needed to be done, often in circumstances that, in the fashion of these times, would not have met the requirements of health and safety or social services. Not all was perfect and we made plenty of mistakes, but many of us in our second careers came to realise, perhaps to our surprise, how much better we often did things in the dependences.

Used to effective financial control and good budgeting, I found it an uphill task when I moved into university administration to get anywhere near as good equivalent systems in place. The Zaria Institute of Administration was opened in 1954, a decade before Fulton and the Civil Service College in Britain. The Outward Bound movement began in the Cameroons. We were used to taking responsibility, not avoiding it, and getting on with whatever needed doing, more often than not on our own initiative.

Kwasi Kwarteng, last year's speaker, is critical of this freedom of the man on the spot to take decisions, but I believe that was one of the great strengths of our Service, and the more I read about how this country has recently functioned the less reason I have to feel any guilt at all. Andrew Rawnsley's The End of the Party, King and Crewe's The Blunders of our Governments and the excellent Diaries of Chris Mullin (what a good District Officer he would have made) all reveal situation after situation that convince me, to use current jargon, that the Colonial Service of our lifetimes, whatever might have happened in the past, was indeed 'fit for purpose'. It was lean, mean, pragmatic, creative and legitimate. By legitimate I mean that in most dependencies for most of the time we governed with the consent of the people. We could not have done otherwise when we were so few in number and our resources were so limited. Most of us, of course, were not directly governing but providing a whole range of services: education, health, agricultural extension, forestry conservation and public works. Everything depended on trust, and alongside that trust there was respect and often affection.

Many historians reject this concept of our legitimacy. They argue that we always knew we could summon the navy as back-up and that we had the support of local collaborators. There is, of course, truth in that, but I cannot say that the navy crossed my mind when on first arrival my District Officer told me to get on my horse and go off into the bush for six weeks on my own to get to know the country and the people. And I do not think it crossed the minds of the villagers who shared my evenings during that six weeks, enjoying street lighting and concert provided by my Tilley lamp and hand-wound gramophone! Neither was the navy much of a help when, towards the end of my service as Governor, I was faced during the Cold War one Sunday morning with the arrival of a substantial Russian fleet. The reinforcement plan in my safe offered a frigate at 14 days' notice!

I associate the term 'collaborators' with Nazi occupation of Europe. I doubt whether any of the chiefs and politicians with whom we worked were ever Quislings in that wartime sense. Where rejection often occurred after our departure it was likely to be because they had become too greedy or too much of a fixture, and then they would be replaced by others who could also be called collaborators.

Where indirect rule was strong, as in Northern Nigeria, it often seemed to me that the traditional rulers had us in their pockets rather than the other way round. I recall an occasion when I took a visiting UK minister to meet the emir, who spoke excellent English but who insisted, as was our custom, on conversing in Hausa. Dissatisfied with my translation, he would readily interrupt me to point out, in Hausa, what I had got wrong, leaving me, with a smile on his face, to fudge suitable answers to the minister's insistent demands of 'What did he say, what did he say?'

Were the sturdy members of the Ellice Island women's club collaborators when, after they had entertained me to tea, they picked me up, tossed me from one to another with great hilarity as they ran down to the beach and threw me into the sea?

Historians, too, sometimes seem to ignore how much change was taking place both at home and in the dependencies within the very short time we were involved - in Africa and the Pacific usually for less than a hundred years. The first initiative in tropical medicine may have been to ensure the health of expatriate staff, but medical services quickly developed to meet the needs of the indigenous population.

My father, as a Posts and Telegraphs surveyor, may have installed the telegraph line from Port Harcourt to Bukuru for the benefit of the Nigerian mining industry, but once installed it was a public service for everyone. We were moving on and developing all the time.

Lugard's Political Memoranda instructed me to provide a mat for a district head to sit on but not to shake his hand. That was not how I treated a district head who had just given me a lift in his Buick! Whatever might have been the views of some of our elders, we need to remember that it was the generation who voted 'Never again' in 1945 that provided the men and women who saw the empire through its final years.

What made the Service 'fit for purpose', often in contrast with what we found in our second careers, was the commitment of its members, a commitment all the stronger because most of us most of the time were working for happy, cheerful people with the support of equally committed colleagues. We were ordinary people doing ordinary jobs in a different environment. Nurse, forester, teacher, road engineer, doctor, inspector of works, vet, police and administrator all shared the hopes and aspirations of the people they served and wanted the best for them and their country. They worked hard for District against Province, for Province against Secretariat and for Secretariat against the Colonial Office.

The interests of the people we served were paramount. If that were not the case we could never have enjoyed the local good relations that so often survived independence and our departure. Until, sadly, he died last year I used to receive every Christmas Day a phone call from a Nigerian Muslim colleague. And it was another Nigerian colleague who took the trouble to locate my father's grave in Dar es Salaam, clean it up and send me photos.

If the history books emphasise what went wrong in Malaya, Cyprus, Aden and Kenya, 'the evil that lives after', so we need to do our best to ensure that the 'good elsewhere does not get interred'. The witness seminars organised by OSPA in conjunction with the Institute of Commonwealth Studies do exactly this, providing for the record a graphic and critical account of what we achieved and what we failed to achieve.

I cite one example: How Green was our Empire? The Colonial Forest Service, following the lead of the Indian Forest Service, took immense care to control timber extraction, to insist on replanting programmes and to minimise disruption to local communities. One of the things that gave me the greatest pleasure when the BBC took me back to Kano was to find that the Communal Forestry Reserves established in colonial times were functioning and treasured. One of the saddest things I have heard this year is that in the Solomon Islands uncontrolled logging is now commonplace, devastating islands formerly carefully protected by us.

There is plenty to remember with pride and I am convinced that just as Ghanaian historians now acknowledge that the slave trade needed African sellers as well as European buyers, just as a hundred years later we are learning to better understand the First World War, so in time there will be a fairer overall assessment of our short lived but extremely effective Service. Thank you.