Our school's got talent: Why pupils' achievements can't always be measured by exams

Mike Griffiths is just back from a trip to Florida, accompanying his school's jazz band on a tour of the States. It is nothing out of the ordinary for the school, Northampton School for Boys, which has built up a considerable reputation for its sporting prowess and achievements in the world of art and drama.

Two rugby internationals, Courtney Lawes and Steve Thompson, are old boys – and the school rugby team has progressed further than any other state school team in the national rugby knock-out competition for schools in the past couple of years.

On the drama front, its former pupils number Matt Smith – the current Dr Who. Its record on both fronts would stand it in good stead in comparison with many schools in the private sector.

It was not always like this, though. Turn the clock back 20 years and it was a struggling comprehensive with only a handful of pupils achieving the then benchmark of five A* to C grade passes at GCSE overall – never mind succeeding in maths and English.

"We had among the lowest number of first choices from parents in the county," he says. "Now we have a huge extra-curricular programme for the pupils. We have hundreds and hundreds of kids involved in the expressive arts and in sport."

The school ensures every pupil can take advantage of what it has to offer. "We have entitlement projects for the whole of Year Eight and the opportunity for a residential trip for the whole of Year 11," he says. "We've got available funds we can use to support pupils if they have difficulties in affording things like a music trip. We wouldn't leave the lead guitarist behind, say, if they couldn't afford to come."

Mr Griffiths, now aged 62 and who first arrived at the school as deputy head in 1993, moves to the centre stage nationally tomorrow when, as president of the Association of School and College Leaders, he chairs his national conference.

At a time when there has been perhaps more friction than light in relationships between the teachers' unions, his is a school that has embraced the Government's reforms wholeheartedly – it was one of the first schools to opt out of local-authority control under the previous Conservative government's plan to give schools grant-maintained status. In 2010, it even went so far as to deliver by hand its application for academy status to Sanctuary Buildings (the headquarters of the Department for Education) when Education Secretary Michael Gove offered the opportunity of applying for academy status to any school rated "outstanding" by education standards watchdog Ofsted.

"It is a very 'can do' school and we try not to let anything get in the way of success," he adds. "We tend to think 'where there's a will, there's a way'.

"If there is one thing which rankles with me, though, it is that, if we have a particularly gifted sports student wanting to come here at the age of 16, we can't give him a place. We have many national champions in music –we've sent dozens of pupils to the conservatoires (specialist higher-education music institutions) – but, if we have an outstanding youngster approaching us who wants a career in music or sport, we can't give him preference."

One episode over admissions sticks out in his mind: a talented 13-year-old organist at another school wanted to defend the championship he had won the previous year. It was taking place in South Africa and the school refused him permission to go – as a result of which he sought to change schools.

"I approached the school about him and they said, 'he's a bit arrogant', says Mr Griffiths. "I think I thought, 'well, if I had that talent when I was aged 13, I'd have probably been the same.'"

The school, which now takes girls in its sixth-form, made its reputation under its previous head, Sir Bruce Liddington, who went on to become the previous government's Schools Commissioner and is now a leading light in the academies movement. He hired Mike Griffiths as his deputy and when Sir Bruce moved on to take up his adviser's post it did not take much to persuade his erstwhile deputy to leave the school in Oxfordshire where he was headteacher and return to Northampton School for Boys.

Asked what academy status had brought to the school, Mr Griffiths says: "I can't really identify it – it's the same culture as when we were grant-maintained. I think the great thing is that we're masters of our own destiny. You have to make your own decisions and stick with them.

"It's a complete move away – there is a bit of the dependency culture with the local authority. There is a bit of a danger, though, that overconfidence can breed arrogance – it's a question of being sufficiently confident to make good decisions and do the right thing."

The school's history does not mean that he has no qualms over the direction education is taking. "I just think we're so much governed by what can be measured rather than what's important," he says. To that end, he would like to see a greater concentration at Ofsted on using inspectors who "have done the job on the ground".

"It's sometimes as if 'we're not interested in anything we don't have objective data for'," he says. "At the same time, I recognise the accountability system is important."

He is critical of the way education is run in this country – not from a party political point of view, though. He cites the fact that, since his school was first established in 1541, there have only been 29 headteachers. "Yet I've seen 18 Secretaries of State in the time I've been teaching and there have been 30 since I was born," he says. "Politicians come and politicians go. School leaders can have a lot longer tenure."

As to the present Secretary of State, he says: "I think Michael Gove is very committed and he's got a lot of positive ideas. However, it is an open secret that even people in his own party are telling him to stop taking the urgency pills and slow down a bit. Schools can manage change – they have to – but there is a limit as to how much you can do. There is so much turbulence in the system that you're in danger of not getting quality."

He cites the problems over last year's GCSE English exams as a reminder that "if you want to introduce change, you have to plan it properly", and he questions how the constant exhortations to schools to improve their performance academically can sit with the plea to the exam boards from Ofqual, the regulator, that they should try to ensure results are broadly in line with those of the previous year.

He also has a word of warning about the dangers of looking back too nostalgically to a past golden era. "To me, it doesn't matter if a B at GCSE is the same as an O-level in 1962 – who cares?" he said. "I remember having a conversation with my dad, who said Stanley Matthews was the best footballer he had ever known, whereas with me it was George Best and my son was saying Ryan Giggs."