For centuries, writers have attempted to predict the future of the human race.

Some have argued that we are destined to evolve into super-beings, others that we are turning into dim-witted goblins incapable of anything more demanding than watching TV.

But according to a leading geneticist, both visions are wrong because human evolution has ground to a halt.

Professor Steve Jones, of University College London, says the forces driving evolution - such as natural selection and genetic mutation - no longer play an important role in our lives.

The people living one million years from now, should Man survive, will resemble modern-day humans.

'We now know so much about the process of evolution that we can make some predictions about what might happen in future,' said Professor Jones in a lecture on Monday.

Evolution is driven by natural selection and mutation.

Genetic mutations create traits which, if helpful, give individuals a competitive edge over rivals.

For most of human history, life was so tough that huge numbers of children died before they reached adolescence.

'In ancient times, half our children would have died by the age of 20.

'Now, in the Western world, 98 per cent of them are surviving to 21,' he continued.

In a harsh environment where people are competing to survive, natural selection is a potent force.

So in Ice Age Britain, a mutation which gave a baby more resilience against the cold or famine also gave it a strong competitive edge, making it more likely to survive and pass its genes on to others.

But in a modern world of central heating and plenty of food, the same mutation is far less likely to give a child any advantage.

Fewer older fathers means fewer genetic 'mistakes'

Professor Jones argues that mutation is also slowing down because of a drop in the number of older fathers, whose sperm deteriorates and contains more genetic 'mistakes'.

He added: 'In the old days, you would find one powerful man having hundreds of children.'

He mentions the famously fertile king, Moulay Ismail of Morocco, who died in the 18th century, and is said to have fathered 888 children. To achieve this feat, Ismail is believed to have copulated with an average of about 1.2 women a day over 60 years.

The professor continues: 'The evolution exam has two papers. Most people pass the first, for they stay alive until they grow up. The second is harder, for candidates must reproduce. The more children they have, the higher their marks.

'Men can score higher than women, for females are limited in their success by the mechanics of pregnancy, while males are free to spread their sperm to a multitude, if they can find them.

Some societies still turn on that simple biological fact. Mohamed bin Laden, father of Osama of that ilk, had 22 wives and 53 children, while his famous son had, last time they were counted, five wives and 22 children.

'Plenty of his henchmen now have no chance of finding a mate and will die without issue.

'The Irish were much the same. A fifth of the men of Donegal share the same Y chromosome - the mark of male descent - and trace ancestry from the same man. In Old Erin's glorious days, marital bliss was an exception.

'Turlough O'Donnell, who died in 1423, had 18 sons. He descended from the High Kings of Ireland, who themselves sprang from a fifth-century bin Laden, a warlord called Niall of the Nine Hostages.

'Niall's chromosome proves how, for centuries, just the mightiest passed on their genes. The weak and the powerful are now closer than they were. The important figure is how much inequality there is in the number of offspring.

'Differences in death rates and sexual success can be combined into a single figure. Across the world, it is in decline. India's cultures range from tribal hill peoples to affluent urbanites, together with millions of peasants, who live as mediaeval Europeans once did.

'Natural selection has lost nine-tenths of its power among the Indian middle classes, compared to their tribal ancestors. The same is true when we compare modern Britain with our predecessors in Darwin's day.'

Decline of 'random change'

A third factor - randomness - is also an important ingredient in evolution.

Small populations which are isolated can change at random as genes are accidentally lost, he said.

But as the world's population becomes increasingly connected, the opportunity for random change is dwindling.

'Almost everywhere, inbreeding is becoming less common. In Britain, one marriage in 50 or so is between members of a different ethnic group, and the country is one of the most sexually open in the world,' Professor Jones added.

'Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that.

'Without farming, the world population would probably have reached half a million by now - about the size of the population of Glasgow.

'History is made in bed, but nowadays the beds are getting closer together. We are mixing into a global mass, and the future is brown.

'So, if you are worried about what Utopia is going to be like, don't. At least in the developed world, and at least for the time being, you are living in it now.'