Mr Gilmour's pieces are made without even a supporting structure of metal or wood.
His sculptures include everything from violins and bicycles to a full-scale Queen Victoria.
Mr Gilmour's passion for using the unusual material stemmed from a desire to promote recycling.
Now Mr Gilmour, who is originally from Stockport but lives in Italy, exhibits his work all over the world selling pieces for thousands of pounds.
"My pieces provoke a chain of thought, thinking about a way of raising the idea of empowerment in the face of materialism and the over-emphasis society places on material possessions," he said.
"I studied art in Bristol in 1997, then returned to Manchester where I had a studio with other artists. I moved to Italy in 2000.
"I was using cardboard originally to make prototypes and models, but the first piece that was a 'proper' sculpture was a life size cardboard cow made in 1998.
"This was made in response to the mad cow outbreak as a substitute for the cows being destroyed, a joke obviously.
"From here I started making more serious pieces and considering cardboard as a very interesting material to make artwork with.
"It is very flexible and has the possibility of calling up other associations with the products which were contained in the boxes I'm using.
"Obviously it's not as strong as more traditional sculpture materials, but I find the challenge of finding solutions to these kinds of problems to be one of the attractions of working with cardboard. The oldest piece I have made is over 15 years old and still looks fine.
"In the end they are no more fragile than works on paper, and even bronzes or wooden sculptures are easily damaged. So long as they are treated with care, and don't get wet, they should last a lifetime.
"The largest pieces I have made are the cars, a fiat 500, a maclaren race car and even the 1960s James Bond. Aston Martin.
"But I also like my smaller pieces like typewriters, guitars and cameras. So far all the pieces have been sold, and there is a waiting list for new works."