A 43-year-old mum has spent the last 20 years amassing an enormous collection of 250 ultra-rare limited edition snacks - including an original 37-year-old Marathon bar.

Food-lover Ali Smith's impressive selection of goodies includes oddly-flavoured crisps, chocolate bars, biscuits, baked beans and even tomato sauce.

Her most prized possession is a Marathon bar dating back to 1982 which she bought on eBay two decades ago for £25.

Among the most bizarre items in Ali's collection are packets of vanilla ice cream flavour Monster Munch and a bottle of green-coloured Heinz ketchup.

The mum-of-one from Sheffield, South Yorks, always buys two at a time, so she can eat one and safely store the other under her bed.

Her collection begun with a special box of Celebrations which only contained Malteser chocolate 20 years ago and has multiplied year after year ever since.

Ali, who works for Sheffield City Council, said: "I bought the Celebrations because Maltesers are my favourite but when I saw 'limited edition' written on the box I couldn't bring myself to open it.

"After that I got a bit obsessed, and every time I saw limited edition chocolate or crisps I had to buy them. "

She added: "I like that they're only released for a short period of time and that afterwards they will never be made ever again.

"Keeping hold of them is like owning a little bit of history."

Included in Ali's collection are 17 varieties of Kit Kat, ten types of Snickers, five different flavours of Twix and four Mars bars.

Despite her impressive assortment of sweet treats Ali said she doesn't "particularly like" chocolate.

"Chocolate isn't really my thing, I can take it or leave it. I much prefer crisps," she said.

Her extensive crisp selection is largely made up of Walkers, which often challenges the public to come up with unique flavours that sometimes hit the shelves.

Over the years Ali has picked up builders breakfast, fish and chips, chilli and chocolate and onion bhaji flavoured bags.

Ali's next addition to her collection will be the brand's limited edition Christmas bags, which are glazed ham, Brussels sprout and pigs in blankets flavoured.

Her most recent addition was a retro pack of Marathon bars which were released last month, 30 years after the brand changed its name to Snickers.

Ali said: "Marathon bars are my all time favourite, I was so annoyed when they changed the name.

"It's great that they've released these retro ones but they're half the size they used to be."

Ali's most unique and unusual item might be a tube of toothpaste which was released to commemorate the Queen's Golden Jubilee in 2002.

She keeps her ever-growing collection in suitcases under her and her husband Andrew's bed.

"We recently moved and getting rid of everything did cross my mind," she said.

"The collection is getting really hard to store because I can't put it in the attic otherwise all the chocolate will melt.

"But I can't bring myself to throw or give it away.

"I think I'm going to do the opposite and keep adding to it instead."

Ali said she hasn't shown her four-year-old son Oliver her stash of goodies.

"If he gets a sniff of it that will be it, the whole lot will be gone."