When Antony Gormley devised one of the most recognisable pieces of public art in the land – the Angel of the North – he wanted to create a work that would serve as a connection between our industrial past and the future of the information age. He had not anticipated that someone would try to use it to flog bread.

But that is what the struggling supermarket chain Morrisons has done – projecting an image of a baguette on to the majestic wings of Gormley's sculpture.

Gormley, who finished the sculpture in 1998, reacted with weary resignation to the news that his masterwork was being plastered with a giant baguette.

"I'd rather the Angel is not used for such purposes, but it's out there," said Gormley, who does not deal with copyright matters connected to the sculpture.

The projection is part of the supermarket's campaign to win back customers, particularly from discounters Aldi and Lidl. It cut prices on 1,200 items by an average of 17% on 1 May.

When he worked on the Angel, Gormley said it had three functions: "Firstly a historic one to remind us that below this site coal miners worked in the dark for two hundred years, secondly to grasp hold of the future, expressing our transition from the industrial to the information age, and lastly to be a focus for our hopes and fears – a sculpture is an evolving thing. The hilltop site is important and has the feeling of being a megalithic mound. When you think of the mining that was done underneath the site, there is a poetic resonance. Men worked beneath the surface in the dark. Now, in the light, there is a celebration of this industry."

The 20-metre-high Angel, with its enormous 54-metre wingspan – each wing weighing 50 tonnes – has been tinkered with before. A few months after it was unveiled, about 25 Newcastle United fans draped a giant replica No 9 shirt, in tribute to their hero, Alan Shearer, across the chest of the statue using fishing lines, rubber balls and catapults. The shirt stayed up for 20 minutes until police arrived.

Morrisons did not respond to requests for comment.