"NUMBER one son" Peter Robinson hates running, heights and sharks but he is prepared to enter a marathon, jump out of a plane and sail around the world for his dad.

A former sales director, Peter, 47, who grew up in Bollington, decided to take time out of work to concentrate on raising £50,000 for Alzheimer's Research Trust when his dad David, 82, developed the degenerative dementia, for which there is no cure, four years ago.

This year the former Bollington Cross and King's School pupil will put his best foot forward and run the London Marathon (on Sunday, April 18), take the plunge in a tandem sky-dive at 15,000ft and set sail on a 10-month yacht race that will take him from the icebergs of the southern seas to the scorching dry heat of the equator.

Although there is little he can do to help his forgetful father, known to some as "Ginger Robinson" from his days as a pro football player for the MUFC reserves, Peter is desperate to help the "under-funded" scientists develop new methods of treatment for the brain disease that effects thousands of people each year.

Peter's brother Dr David Robinson, 43, noticed that their dad was being "too forgetful" and arranged for him to have a CAT scan, which confirmed their worst fears - he had Alzheimer's. Now David senior, who lives with his dedicated wife Eileen, on Princess Drive, Bollington, is on medication but unfortunately his condition can only get worse.

Eileen has been married to David for 53 years, she said: "Sometimes I feel like I can't move at all because I need to keep an eye on him. I can't even nip to the loo or he'll have the fire guard off and be playing with the gas. One of the most obvious symptoms are his obsessive traits. He is constantly tidying up. He might clean the kitchen and then ten minutes later he'll do it all again.

"He'll ask the same question 20 times in one hour. It is quite humorous at first but imagine doing it all the time. One night last year he got up about 3am and got fully dressed. I told him to get back in bed because I wasn't going to make him breakfast. Other days he'll sleep until the afternoon.

"We don't go out to many places anymore. A friend of mine takes me shopping but we had to take the car off David and I never learned to drive. I don't like to think about what Peter plans on doing. I think the whole thing is wonderful but I wish it was someone else, someone I don't know taking the risks. Why couldn't he do something normal?"

In just four days time Peter will pull on one of the Alzheimer's Trust's purple t-shirts and join thousands of people to run the 26 miles in the London Marathon. The dad-of-three to Claire, 20, Laura, 18 and Alex, nine - who also lives with his wife Ged, 43, in Buckinghamshire - has so far run a maximum of 18 miles in training.

"I am relying on the adrenalin and the crowds. They say that does help a lot. The plan is just to get around in four-and-a-half hours, which would be good for an old man."

And later this year he will complete the tandem sky dive: "Jumping from a plane at 15,000ft is not my idea of fun.

"It is just the looking down that is going to get me. I can't even stand on the edge of a cliff. I am sure it'll be the hardest thing for me to do even though it is the easiest for me to train for."

But the real dangers are surely going to be during the 'Global Challenge 2004/5', the world's toughest yacht race. Amateur yachtsman Peter will be one of the 17 ordinary men and women and a professional skipper to crew a 72ft ocean racing yacht.

Along the way the team will face 50ft waves, 70mph winds and giant icebergs but Peter says he is looking forward to the arctic temperatures and dramatic landscapes that few other people can claim to have experienced.

"I just like to challenge myself, to do something different. I have not taken a break from work for 25 years and I signed up four years ago to do the sailing. I had never sailed before and have now had a bit of practice.

"They encourage you to do as much sailing as possible. Fortunately l am not seasick, as there are not many people who can say that they have sailed around the world."

Together the crew will also get the chance to explore Buenos Aires, Wellington, Sydney, Cape Town, Boston and North Europe and the opportunity to walk away with the prestigious Princess Royal Trophy. But Peter added: "At the end of the day it is about finishing the race safely."

Although there will be no phones aboard the boat Peter and the rest of the group will be able to keep their loved ones up-to-date by sending digital pictures and letters via the Internet.

"I am not so interested in the travel because I have flown all over the world on business," Peter said. "The most exciting bit for me will be sailing through the ice, seeing giant waves and other amazing things that other people haven't seen. Being in the middle of the southern oceans - 2,000 miles from the closest land - will be the closest I come to being in space.

"At times we will have to be clipped on to the boat to stay aboard. Last year one guy got his leg smashed against the wheel when his boat was hit by a gigantic wave. They had to turn around and take him to dry land.

"The most important thing is doing this for charity. Alzheimer's Research is a very under-funded charity. Rather than provide support to help the sufferers these people actually do research into the brain to find the root of the problem. They only get about £3million a year, which is not much when it affects so many people."

If you would like to sponsor Peter in his 'Ultimate Triathlon' then please either send money direct by ringing him on 07785 257902 or log-on to www.justgiving.com/theultimate