Prince Charles has submitted a signed work of art for a huge charity exhibition near Bristol but, as Tim Davey discovers, it's not all oils and watercolours on show – some of it is knitted!

Shapeless, woolly jumpers, bobble hats and baby cardigans are the stuff normally associated with those who knit for a pastime.

Dianne Bendle, though, turns that sort of traditional thinking on its head. When she "knits" she does it big time. And I mean big.

For example, Dianne's latest project requires her deftness of hand to knit on needles that are each a whopping 15ft long. The aim is to produce a unique work of "knitted" art. Dianne, who graduated in Bristol and lives in a little village near Midsomer Norton, is renowned for creating exhibits with outsize needles, using unorthodox materials.

The needles are crafted by her husband Geoff Bendle, who's a woodworker.

"They are made out of hardwood and I have got lots, all different sizes and thicknesses," explains Dianne.

None of them, though, are as big as the jumbo 15ft pair she's using to craft a special piece for a particular exhibition. It's going to go on show at the Penny Brohn Cancer Care charity headquarters in Pill, near Bristol, as part of a major fund-raising exhibition of artwork.

There will be more than 400 pieces of art on show and the organisers are hoping it will raise £50,000 for the centre and its work.

Dianne's mega needles have already produced one piece for the show which stands 10ft high, and another slightly smaller piece will follow.

"I am using foil as the material," she reveals.

Each of her pieces carry titles culled from what Dianne describes as "forgotten" words, ones rarely used in dialogue any more.

Her work for the Penny Brohn Cancer Care exhibition, she says, will be called Fulgent – a word which means "resplendent, bedazzling, brilliant, bright and shining".

The Penny Brohn exhibition is a new event for Dianne, who says: "I was contacted and asked to submit some work and they got quite excited about it. It will need a bit of space, though, and I will bring the needles I have been using."

Dianne sits on a stool to knit her works (even with the big set of needles), and the materials used are many and varied including elastic bands and zips. She adds: "Some are quite difficult to work with, especially lengths of clothes line – the plastic ones with a metal core inside."

Dianne studied and worked at Norton-Radstock College, gaining a diploma in fine art, followed by three years at the University of the West of England (UWE), graduating with a first class honours degree in drawing and applied art in 2007.

Incredibly, given her field of art, she says there's something she cannot do, and that is to knit in an orthodox way. "I can't knit a jumper or anything like that," she reveals.