When Simon Knight returned to Helena Romanes School and Sixth Form Centre in 2004 as head teacher, he found a school that had “radically changed” from when he left his post as head of PE three years previously.

Staff turnover was high while pupil behaviour had deteriorated. His job, as he puts it, was to "set about rebuilding the reputation of the school".

After a 36-year career in teaching, 16 of them as head teacher at Dunmow's Helena Romanes, Simon will retire on August 31.

After his appointment, Simon focused on finding "quality" teachers to fill the gaps and strengthening the school's ties with the community.

He said: "I remember a previous head at Saffron Walden County High said changing the culture of a school is like turning an oil tanker round. It takes forever to set it on its new direction. It took me probably four or five years to change the culture to the one you see today, where children want to come to school."

In 2009, the school achieved a "good" rating in its Ofsted inspection, which, according to Simon, is the "first time" in the school's history that it has gained such a rating; a "real achievement for everyone in the school".

In March, Simon was one of thousands of head teachers who co-authored a joint letter to families, warning of worsening budget shortages for schools.

"There's been a real drop in funding for schools," Simon said, "there are three schools in this area, Saffron Walden County High, Joyce Frankland Academy in Newport and ourselves, that are below the minimum funding guarantee for schools, and that has brought huge problems. I spend probably most of my life looking at funding, trying to balance the books. And we have done a reasonable job but it gets harder and harder every year."

Some 80 per cent of the money available to Helena Romanes is spent on salaries and Simon has had to make members of staff redundant, which he says is "a horrible thing to do".

"Every area comes under scrutiny," he continues, "There is going to come a point where you just can't make any further cutbacks. Schools are effectively going to go bust if you're not careful. We just about balance in year and we've got some carry forward, but not much. There needs to be a greater input into funding for schools."

So how is the lack of funds affecting pupils' education? "There are larger class sizes," Simon says, "We probably don't do as much as I would like us to do with some additional areas, things like counsellors in schools, we have some but we don't have a lot."

Children are under more pressure now than they have ever been, he says.

"I think there is a much greater pressure on kids now to get results. We will never be an exams factory. I think it's much more about children leaving happy and having had a good experience. We had a Duke of Edinburgh expedition at the weekend and I received an e-mail saying the pupils were absolutely fantastic and you just think 'that's what school should be about' as well as exam results."

When Simon was a PE teacher at Helena Romanes a group of students took part in a programme where they learnt how to build motorbikes.

"I would love for us to be able to do that again. Some children can't cope with this academic curriculum. If I had more money I would make the curriculum much wider for those sort of children," he said.

There are moments Simon will never forget, such as white water rafting in Zimbabwe with students as crocodiles looked on, and taking 250 children to Dourdan in France.

So how will he feel next week, when the school is preparing to break up for summer? "I'm a bit worried I am going to be really upset. But I have loved it. I'm tired and I'm ready for a new challenge but equally this has been my life and, as head, it really is 24/7. I am very proud and privileged to have been the custodian of this school for 16 years. I have passed the school on in better hands then I inherited it and I look forward to seeing the school develop in the next few years."