When Wolverhampton College executive Lesley Cross bought herself a little black dress from Debenhams in a size 14, she told the shop assistant it was for her sister.

At the time she was a staggering 30st 3lb and could barely have fitted one leg into the elegant party frock.

But she bought it with the intention of one day being able to wear it and for the next 16 months the dress was the inspiration behind a remarkable weight loss of more than 19 stone.

Lesley’s wake-up call came at her 50th birthday party at Bishops Wood village hall in Staffordshire two years ago for 80 family and friends, including colleagues from the Paget Road campus where she is director of student support.

But when the night came, she was too tired to leave her seat and some guests, whom she had not seen for years, were shocked at how big she was.

Afterwards a friend, Chris, gave her an album of photographs as a memento of the evening. “When I saw myself, I realised I had to do something. My dad said it was like watching me commit suicide in front of his eyes – I hadn’t realised how much my weight had affected the people around me.”

Lesley went on a liquid-only diet for the next 16 months and for her first meal after achieving her target weight, she wore her little black dress. “It was an emotional moment,” said the 52-year-old.

“Ray said we should make it a family meal but it was such an emotional moment for me, I needed to be on my own. I’d been planning the meal for ages – salmon cooked in foil with a green salad – and for a while I just sat there in my dress in the kitchen just looking at it feeling a mixture of fear and ecstatic happiness. I tasted every leaf.”

Lesley has found a more comfortable weight of around 11st 10lb and has taken up pilates and aqua-aerobics. Later this year she hopes to undergo surgery to remove the excess skin caused by her weight loss.