Dramatically caught on camera, plumes of fire and smoke erupt from a classroom laboratory desk in May 1978 as part of an experiment to show zinc sulphide synthesis.

Ham & High: Highgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's DiaryHighgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's Diary (Image: Archant)

It is just one snapshot from chemistry teacher Andrew Szydlo’s 40-year career at prestigious Highgate School, meticulously captured over the years in striking photographs.

His images tell the story of day-to-day life at the North Road school between 1975 and 2015, and are now on permanent display in a book entitled Schoolmaster’s Diary.

It has been released to tie in with the school’s 450th anniversary.

Mr Szydlo, 66, said: “Obviously, all sorts of things have changed since the 1970s but most importantly, the book shows that children don’t change.”

Ham & High: Highgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's DiaryHighgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's Diary (Image: Archant)

The father-of-two added: “I think the photographs show the reality and the humour of school life.”

Starting in 1975, the first few images document Mr Szydlo’s early years at the school, teaching chemistry and taking pictures of every aspect of school life, from classroom experiments to snow days.

One photograph shows three gruff-looking boys standing together wearing old-fashioned sportswear.

The caption tells the dramatic story behind the picture, of when a group of Junior School athletes were locked into a dressing room at Barnet Copthall Stadium by other school teams in July 1976. Mr Szydlo, an amateur photographer who has held more than a dozen exhibitions, remembered: “We were perceived as being a bit of a posh, public school with our uniform and everything. There was quite a lot of local rivalry. There was a lot of fighting between other schools, nothing serious, but a bit of gang warfare.”

Ham & High: Highgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's DiaryHighgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's Diary (Image: Archant)

The “siege” ended when the three Senior School athletes captured on film managed to force the door open, releasing the young pupils.

Another photograph shows a pupil dressed in uniform and wearing a gas mask, in front of a huge plume of smoke, in October 1980.

Mr Szydlo had just demonstrated the hydrolysis of silicon tetrachloride to A-level students, an experiment which produces a violent reaction.

Having warned his pupils the previous day about how much smoke would be produced by the reaction, one pupil came prepared to the lesson with a gas mask, providing Mr Szydlo with an unmissable photographic opportunity.

Ham & High: Highgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's DiaryHighgate School teacher Andrew Szydlo has documented his 40-year career in a book called Schoolmaster's Diary (Image: Archant)

The book even contains an early “selfie” of Mr Szydlo with five of his pupils in June 1979, taken on a camera with a wide angle lens.

The final few images show current pupils with biro on their hands and with smartphones, completing the 40-year narrative.

Mr Szydlo, of Onslow Gardens, Muswell Hill, produced the book after putting together an exhibition of his images at school for the milestone anniversary. He said: “I always used to document everything, I have masses of photographs of everything in my life. But I never realised when I started how long I would be at the school.”

Email oc@highgateschool.org.uk for a copy of the book priced at £12.50 including postage and packaging.