The posters proclaiming “LBS - London’s Best School” might seem like something of a joke, except that acting head Yvonne Bates is perfectly serious, and so are the pupils and teachers.

LBS actually stands for Lilian Baylis School - one of the 18 schools named by ministers in June for its poor academic and attendance record, and its apparent failure over the past three years to shake off its failing school label.

Today the south London school is aiming for the top. The pupils have to believe they are the best, according to Ms Bates, because it sustains their motivation and self-esteem.

“Pride” is one of Ms Bates’s favourite words. When she arrived at LBS in September, she told the children she was proud to be their new head. They, in turn, are expected to take pride in themselves and their school.

Ms Bates was seconded to LBS from Nobel School in Stevenage, Hertfordshire, where she was deputy head. When she arrived, she asked Lambeth education authority to redecorate the school and move some facilities from an annexe into the main building.

“It was ridiculous to have children crossing a busy road to get to technology lessons when we have 500 pupils in buildings able to accommodate 1,500. ”

In the six weeks since term began, attendance has increased from just over 80 per cent to 90 per cent, punctuality has improved and almost all pupils are wearing full school uniform.

“Just look at that one in her trainers, she is letting herself and the school down and she knows she is,” said Ms Bates from the vantage point of her office. The 15-year-old sneaked a guilty glance upwards, then ran off quickly, realising she had been spotted.

“I have high expectations, which are shared by the staff. They do not tolerate bad language or bad behaviour. It would be easy to let these things go when there are other issues to address, but it all has a knock-on effect.

“The children have this idea that I’m very strict. I don’t think I am. But I noticed when I arrived that there is a huge loyalty and pride here, and I suppose I am using that to get the best out of the children.”

It is a psychology that is reaping huge rewards. An interim visit by inspectors in the last two weeks was so positive that they recommended a full Office for Standards in Education inspection as soon as possible, with a view to taking the school off special measures.

LBS, which was found to be failing in 1994, was making steady improvements even before Ms Bates arrived. GCSE results have significantly improved in two years, with 17 per cent of pupils gaining five or more top grades last summer, compared with only 8 per cent in 1995.

Two years ago, almost 7 per cent of pupils were not entered for any examinations. In 1997, all sat at least one GCSE.

Ms Bates’s chief role has been to consolidate the progress already achieved, and gain a clean bill of health for the school.

However, the highlighting of Lilian Baylis by ministers in May as one of Britain’s worst schools was a major setback at a time when things were getting back on track.

“It was terribly disappointing for everyone, particularly the children who were publicly branded as failures, attending a failing school. The pupils deserve better than that. When I first came to have a look around I did not get the impression of a school in disarray. It was a very orderly place.

“But there were issues that needed to be addressed. Children were coming here with low levels of literacy, and there were problems with absenteeism and punctuality which are now being addressed.

“People now come here and express surprise that the school is on special measures,” said Ms Bates.

Even so, LBS has some way to go before it can be dubbed the capital’s best. For the time being, “London’s fastest-improving school” might be more appropriate.