Super-head Marie is in a class of her own.

All of Britain was shocked when, in 1995, a popular headmaster. Philip Lawrence, was stabbed to death at the gates of his school in North London.

St George’s Roman Catholic School in Maida Vale had become plagued by gang violence, truancy was commonplace and disillusions and scared teachers were incapable of maintaining discipline.

An inspection deemed the school to be failing and it was earmarked for closure. Its only chance was to draft in a so-called super-head, who was given a year to turn the school around.

The person chosen for that task was Marie Stubbs, a recently retired Scottish granny with previous experience of being a headmistress at several schools.

However Marie was no ordinary granny and succeeded despite opposition from pupils, gangs, parents and even fellow teachers. Her unorthodox methods saved the school.

She wrote a book, Ahead Of The Class, about her experiences and it has been made into an enthralling TV drama to be screened next Sunday on ITV1, with Julie Walters as Marie.

Seeing Julie and Marie sitting side by side, its easy to see the mutual respect, they didn’t meet before filming, but afterwards were delighted to swap experiences and have become friends.

You might think that Marie would have been wary of putting herself into what was, at times, real physical danger at St George’s but she thanks her Glaswegian upbringing for giving her strength.

“To cope in situations like that you have to be kindly yet canny. I grew up in the East End of Glasgow and you really had to become streetwise, I used to get on tramcars every Saturday night and I learned to engage with all sorts of people. You use a combination of canniness’ and caution.” She said.

There were times when she was in real danger at St George’s.

“There was one occasion when someone held a piece of glass to my face. I just tried to stay calm and said ‘Do you think you could see what the time is on that clock? I’ve left my glasses at home’.

“One of the first things I told the staff was that they should never be seen to be running around. Running makes it look like there is a crisis,” she said.

Playing a remarkable headmistress was a dream for Julie.

“I found the book totally inspiring. Teachers get such bad press. I was terrible at school! I was just a clown really, always trying to be funny. I got thrown out of sixth form because I simply wasn’t doing enough.

“I threw the letter away and didn’t tell my mum until I was 35!” she laughed.

Julie’s admiration for Marie is total. “I’d have crumbled if the teachers hadn’t been on my side and I would have hated all the confrontation.”

Marie is thrilled to be played by Julie, who is one of her favourite actresses. But after seeing the finished film there was only one thing she noticed that was different.

“Julie has a better figure than me. I thought her hair and clothes were much nicer than mine. There’s one scene where she wears a necklace at a posh May Ball and I could never aspire to such glamour.” She said with a twinkle in her eye.

“I enjoy things like weight training, ice skating and skiing. I need to keep that up now I have seen Julie looking much better playing me!

Ahead Of The Class is a fascinating, moving and inspiring piece of TV with the supremely talented Julie Walters doing justice to the supremely talented Marie Stubbs.