At 65, software whizz Paul Humphreys says he should be putting his feet up at the seaside — but he is still as enthusiastic about computing as he was at 18.

He runs four businesses — a computer training studio, a community website, a computer consultancy and Frittter, an online accountancy firm.

His latest venture, frittter.com, is based, like the others, at his home in Kidlington, where he has worked since leaving his job as subject officer for computer studies at Oxford University.

Frittter's accountancy software allows small or medium-size businesses to input their transactions, while flesh-and-blood accountants use the data to produce figures for company records and tax.

He said: "I was the first person in the UK to receive an Apple micro-computer and I have always retained a boyish enthusiasm for computing. I should be putting my feet up on Brighton beach, but I am always developing new systems.

"It is a great privilege to have had that background because it all goes back to first principles. Since I set up on my own, if I feel a project is really exciting I can go at it with full-blooded enthusiasm."

Frittter was born after he experienced problems producing accounts for his own businesses.

"I have had a number of accountants and I thought it would be nice to write an accounting system from the point of view of a client rather than an accountant.

"From my experience accountancy systems are written for accountants. I have produced something that is very easy for the client, but gives all the numbers that need to be manipulated in the way that accountants need.”

So far he has a dozen clients and four accountants, all based in Oxfordshire, specialising in different areas such as legal firms, science start-ups or education.

He said: “We are unlike other online accountancy websites in that we have real flesh-and-blood accountants able to take over and advise clients.”

Each client also has a back-up accountant. "A lot of small businesses come to grief because their accountant leaves, but we have a number of people looking at the system."

As well as running Frittter, Mr Humphreys has set up kvoice.com, a Kidlington website which, he says, could transform community Internet sites. He is also working on an online booking system for restaurants. His website is www.frittter.com