Ask BBC's 999 stuntman Marc Cass to jump out of an aeroplane, drive a car into a river or fall through a frozen lake and swim under the ice, and he won't turn a hair. Show him a spider, and his knees turn to jelly. Marc is one of Britain's five per cent of people with a phobia - an irrational fear which in severe cases can prevent sufferers from leading a normal life. A brave man, he volunteered to confront his darkest fears on TV.
To demonstrate what phobias are - and how they can be cured - the BBC 999 team enlisted the expert help of two OU specialists. Dr Peter Naish is a cognitive psychologist who treats phobics, and Dr David Robinson is an expert in handling insects and arachnids (spiders) as part of his research into how animals communicate by sound.
For the session, filmed in a OU/BBC studio on the Walton Hall campus, David had rounded up some creepy crawlies guaranteed to bring out the phobia in Marc: giant African millipedes, spectral Australian stick insects, huge brown hissing Madagascan cockroaches, and a big hairy tarantula.
Despite their alarming appearance, all are harmless to humans - but knowing this would be no help to a phobia victim like Marc, because the fear he feels comes from a primitive part of the brain, Peter Naish explained.
"Rationalising is no cure. Any phobic will wring his hands and say `I know it's stupid, but I can't help it'. You have to meet it on its own grounds."
There are two techniques generally available to treat phobias, says Peter - desensitisation and `flooding'.
"Basically, you just flood the person with the thing frightening them - throw them in at the deep end. Their body produces a tremendous fear response, but cannot keep it up. Gradually, the body learns `this is not harming me' and the response goes away."
It is important to say that this is not a treatment that he would recommend for most phobics, he adds.
Terror brings on measurable physical changes in the body and part of Peter's role in the 999 experiment is to measure it.
"If you are frightened, your heart beats faster, and you breathe faster, giving you more oxygen - that is the `fight or flight' reaction. Blood runs away from your extremities to the core, so that hopefully, if you're injured, you won't bleed to death."
Marc sits in front of the cameras, his hands strapped to the table in front of him. Peter attaches two electrodes to the palm of Mark's hand to measure electrical resistance, which decreases as Mark begins to sweat with fear at the sight of the creepy crawlies. He also sticks electrodes to Marc's chest to measure changes in his heart rate and breathing.
David begins with the least fearsome bug in his collection. "It's a female prickly stick insect," he explains, as …