Breathing in the choking fumes of a busy London street was squeezing the life out of Mike Fielding's lungs.

The 13-year-old has suffered from severe asthma since birth and the densely populated capital barely offered room to breathe.

During the winter months, Mike would live in fear of the city's fog as the thick clouds trapped pollution in the atmosphere and frequently sparked an asthma attack.

Summer offered no respite. Mum Jackie would call the youngster inside at 3.30pm sharp. Any later and the hazy heat, combined with dust and the diesel vapours of passing traffic, would be too much for his fragile chest.

Mike and his mother were getting desperate.

Jackie, 45, said: "Mike was a very poorly boy. He would often have an attack just walking down the street. Every six to eight weeks things would become so bad he'd be admitted to hospital.

"The pollution did not cause his asthma but it could trigger an attack. Although his school was only a five-minute walk away I would have to drive him there.

"In winter, the fog would sometimes be so bad we would have to wait until it cleared before we could set off. In the summer it was ridiculous because I had to keep him indoors in the afternoons when he should have been outside enjoying himself with other children.

"We had to do something because he had no quality of life at all."

The final straw for Jackie came four years ago after Mike suffered a particularly bad asthma attack.

She said: "Mike was hospitalised and then diagnosed with double pneumonia. His consultant advised me to get out of London as we were both becoming prisoners in our own home."

Help was at hand in the form of Jackie's sister Pat, a nurse from East Grinstead. The family noticed the air there was much cleaner than in London as traffic was not condensed into narrow streets causing pollution to build up and saturate the atmosphere.

Jackie said: "We realised every time we came down here Mike would get better. But when we decided to move it was still a very big decision.

"It was terrifying because we were leaving behind a care plan for Mike and we had become very reliant on the local hospital. I also had to leave all my friends.

"But we have been lucky and everyone down here has been very good to us."

Mike and Jackie took the plunge four years ago and have not looked back. The teenager is now happily settled at Sackville Community College and is enjoying life again.

"The school has been fantastic," Jackie said.

"Mike is a very clever boy so he doesn't need any educational help but someone always looks out for him in case any of the classes, like woodwork where there is a lot of dust, cause him a problem.

"There is also excellent medical support in this area which we could not get in the inner city. We have a community sister at Crawley Hospital who we can contact whenever we want and Mike has regular check-ups from a consultant.

"All this has given Mike more confidence and he has been able to make lots of new friends. As long as he gets the right protection he doesn't have to worry constantly about having an asthma attack and he has a much better life all round."

For more information on coping with asthma, contact the National Asthma Campaign on 0845 7010203 between 9am and 5pm.