Black Sabbath's Tony Iommi in glass box for cancer awareness

Black Sabbath's Tony Iommi spent a few minutes inside the two-way mirror box

Heavy metal legend Tony Iommi has been shut inside a glass chamber in Birmingham to highlight the loneliness felt by people diagnosed with cancer.

The Black Sabbath guitarist - diagnosed with cancer in 2012 - spent a few minutes inside the "isolation box" much to the delight of nearby shoppers.

MacMillan Cancer Support was behind the exercise, which was carried out in the city's Bullring shopping centre.

"I was in a bubble for a while - just like the isolation box," said Iommi.

Tony Iommi said he thought "it was the end" when he was diagnosed

He has been making music professionally since the late 1960's

The chamber is made from two-way mirrors that stop the inhabitant seeing out but allow other people to look in.

Those inside the box can hear recordings of personal stories from cancer survivors.

'Absolutely devastated'

The Birmingham-born musician, who was diagnosed with stage three lymphoma, said the box went some way to conveying the isolation he and many other cancer sufferers felt.

"When I was diagnosed I was absolutely devastated," he said.

"They're talking to me saying 'you've got stage three' and it's going in my head and I just felt somewhere else.

"And it was only later when I really broke down, I thought that's it, it's the end. And you really think that.

"But it's not. There are people who can help."

Iommi has undergone surgery and chemotherapy and said he was feeling well and looking forward to jetting off to Los Angeles to work.

Tony Iommi (l), Ozzy Osbourne (centre) and Geezer Butler (r) formed their first band in 1968

Inside the box: Jennifer Meierhans, BBC News

Once the door shut I was surrounded by my own reflection, but if I looked closely I could make out the hustle and bustle of shoppers going about their day.

It gave the impression of being trapped in one place while everyone else's lives went on as normal.

I was very aware that everyone could see me but I could not see them - which made me a little self-conscious.

But at the same time the walls made me feel invisible.

Listening to the stories of cancer survivors was moving and the box provided was a quiet space to think about how other people could be feeling.

One of the cancer survivors who shared her story in the isolation box was Niki Meller, from Rednal in Birmingham.

She was diagnosed with breast cancer five years ago and underwent surgery and reconstruction.

"Although you have support it's a very isolating time," she said.

"During my diagnosis I had an out of body experience where I was sort of looking down on myself.

"The oncologist was saying about having chemo, surgery, radiotherapy, reconstruction, but my thoughts went to my friends and family and how they would cope with it."

New figures released by MacMillan reveal an estimated 550,000 people in the UK - 22 per cent of those living with cancer - suffer with loneliness.

Niki Meller's cancer survival story was played to shoppers inside the isolation chamber