It is a mystery that has perplexed psychologists and philosophers since the dawn of humanity: why are most people honest?

Now, using a complex array of MRI machines and electrocution devices, scientists claim to have found the answer.

Researchers at University College London discovered that at a physical level the brain finds decency far more satisfying than deception.

The trial revealed that, despite accumulating a large amount of money, most participants derived no deep-seated satisfaction if the success was gained at the expense of others.