LESLEY was just yards away from finishing the final, formidable mile of the London Marathon when she let go of the Breast Cancer Campaign balloon she had been carrying all the way through.

She sprinted the last lap and shone with obvious pride as the pink balloon floated up towards the sky, its logo displayed to thousands of cheering spectators.

It was a poignant moment - kissing the balloon before letting it go and she felt a great surge of energy despite the tired limbs and aching body. The race hadn't merely been about running 26 miles or proving she was still fit at 42.

The message on the balloon stood just as much for why she was running as any sense of personal achievement.

For only a few years ago, Lesley was battling breast cancer and she wanted to give something back after her brush with the deadly disease.

Minutes later, she was given the news she'd run the marathon in under five hours and that she will have raised £1,100 for Breakthrough Breast Cancer and the Heart Foundation.

"It's one of the most important moments of my life," says Lesley, an accounts supervisor for The Northern Echo, from Darlington.

"I did it for breast cancer sufferers everywhere and for my father who died of a heart attack, as well as for Northern Echo photographer Ian Weir, a friend who died waiting for a heart operation."

Four years ago, Lesley had been taken into a room by a hospital consultant who was examining a tiny lump and was told she had cancer.

"He said 'you've got breast cancer'. I couldn't believe what I'd heard. I said those words to myself over and over all the way home to prepare myself for telling other people," says Lesley, who was North-East wind-surfing champion from 1995 to 1997. But no matter how many times she repeated the chilling words of the consultant under her breath, they wouldn't sink in.

The tiny breast lump was actually found by her husband Barry and she hadn't worried about it, so the news of cancer hit her hard. It was only when she got home and rang her office that it finally sunk in.

"I phoned up and said I've got breast cancer," remembers Lesley, who is hoping to be a Breast Cancer Care volunteer. "Afterwards, I just crumbled. It was telling someone else that brought it home to me. You hear you've got cancer and you think you're going to end up in a box. I waited by the gate for Barry to come home from work and when he saw me waiting there, he knew. I never usually wait for him."

Lesley went straight into hospital for a lumpectomy in April, 1997 and was told the cancer was aggressive and may have spread further into her breast. The surgeon at St John of God Hospital in Scorton, near Catterick, left her to make the decision to have a mastectomy. It didn't take much time for her to decide to go for the operation - she didn't want to gamble with her life if the cancer had gone further than the lump.

'I had the mastectomy a week later, on my 39th birthday," says Lesley. "I didn't want to take a risk with my life so I decided to have it done. You only get one life and I was determined to get though this. It was a good thing I did have the mastectomy because they found further cancerous cells in the breast."

Lesley had never checked herself before the breast cancer. "Barry pointed out this hard, pea-sized lump to me and asked, 'how long have you had that there?' But it didn't scare me at all. I really thought it was nothing," she recalls.

She was suffering from tennis elbow at the time and she was more concerned about recovering from that. She had a doctor's appointment already arranged for it and thought she may as well mention the lump. So she was surprised when the doctor sent her to the breast clinic hospital straight away.

She says: "I can't stress the importance of checking yourself regularly for lumps. I remember thinking, this can't be. I'd exercised all my life, I'd wind-surfed, I always ate healthily. At that time, I thought cancer happened to people who were not very healthy. Now I know different, of course. It can happen to any of us at any time."

Since the mastectomy, her life has changed dramatically. She had six months of intensive chemotherapy and took Tamoxifen which brings on early menopause and her left arm is always swollen with lymph fluid as a result of her surgery, which made wind-surfing increasingly difficult for her. It would have been easy for Lesley to give up her action-packed life and cash in her gym membership after the major surgery but she was determined to keep on going as strong as ever. She was off work for two months to convalesce and, while she stopped appearing on the national wind-surfing circuit because of the arm, she managed to find herself another enormous challenge.

"I've always loved team sport and keeping fit. I love a real challenge - I even auditioned for the TV show Gladiators at one point. And in a moment of madness, I sent off for an entry form for the marathon. Me, small, round and not in the first flush of youth, entering a run of 26.2 miles! My colleagues thought I'd finally flipped when I told them. I was both excited and terrified at what I'd let myself in for."

She got up at 5.30am most days to run before work and trained with the Darlington Harriers one evening a week. She started running for charity three years ago when she completed the Great North Run. But every last stride of that 13-mile race was a huge challenge at the time and she never imagined running it again - let alone running a race twice its length.

"I think the cancer's made me more determined, it's made me think 'I can do it'. When I finished the Great North Run I thought there's no way I can run a marathon - I couldn't have even contemplated it. But then, when I was given the opportunity last year, I thought, why not go for it, you only live once!"

She says she has never felt fitter or happier than she does these days. She recently wore a strapless dress and paraded on a catwalk as a model in a charity fashion show which gave her a wonderful, newfound confidence.

The breast cancer support group she's been a member of over the last few years may have been a traumatic way to meet people but she's made the most invaluable friends though it.

And although she's considering breast reconstruction, she's putting that on hold for the moment. She's too busy living life to its fullest right now.