The fellow who traded archives for red boxes

John Redwood tells Martyn Kelly why he decided not to become a historian.

In 1976 a young historian wrote about the effect of the age of Enlightenment on the political and religious establishment of the day. "Such physical and ethical decay," he wrote, summarising their views, "brought decrepitude, the decline of marital values, the decline of moral health in the nationI". Almost 20 years later, the author of those words is embarking on his own moral crusade for the health of the nation. "We have to reassert," he said recently in an interview with The Independent, "that we believe in the traditional family."

Yet John Redwood, former Welsh secretary and standard bearer of the radical right, sees no link between these two phases of his career, although he was already a county councillor in Oxfordshire as he worked for his DPhil at Oxford "I always saw being a historian as rather different to being a politician," he explained as we discussed the stages that had led to his first book, Reason, Ridicule and Religion.

Redwood worked on his dissertation for two and a half years, first as a postgraduate at St Anthony's College and then as a fellow of All Souls. At the end of this time, and with the reading complete, he got a job in the City and started to think about writing his dissertation. "I completed it on the tube on my way to work each morning," he explains. "I had got it all on card indexes, in the way of those days, and I took all the relevant cards for the next chapter on the tube and sifted my way through them. I finished off the writing in the evenings and I did all the proof-reading on the tube. I had an hour each way so it was a productive use of time."

One feature of the Enlightenment which interested Redwood was the rise of satire and irony as tools in the great debates of the day. "Ridicule was the most damaging weapon," explains Redwood. "It is still true. If you want to make a speech that is effective, putting a point across in a humorous way often makes it far more memorable than making it in a straight way."

Before the Enlightenment, Redwood continues, "the task of learning was to explain what previous great thinkers already knew. Then along came these people who said that it was also about seeing new things - studying insects through microscopes that the ancients didn't have or studying planetary motions through better telescopes.

"Within the intellectual ferment of the late 17th and early 18th century in England there was a great fear that knowledge itself - the new discoveries - would trigger irreligion and that it would in some way upend the traditional arguments for God and His miraculous works. I looked at the way in which people tried to counter this and graft the new learning on to the old theology.

"I finally decided to give up being a full-time historian because I felt I was very much a figure of the 20th century and, while I did my best to be an independent historian and immerse myself in the ideas, views and events of the time I was writing about, I was also very interested in my own period. I decided that I needed another career to pursue those interests more strongly.

"As a historian I tried to be independent and neutral. I tried to be above the battles and conflicts that I was describing and to be fair to all sides. As a minister I tried to be fair to all sides but, as a politician, I clearly have strong views and opinions that would not be compatible with writing good, clear, honest history."