SOUTH Essex has never been much of an old school county, either figuratively or literally. In Essex, people have always become rich and famous because they were made of the right stuff rather than because they went to the right school.

Yet one south Essex establishment does qualify for a place among the stately old schools of England. Brentwood School, which this years celebrates its 450th anniversary, has never been much good at snobbery or class barriers. But in terms of history and pride in its traditions, it can give Eton or Marlborough a run for their money.

The school can also a list a pretty starry line-up of recent alumni. They include former foreign secretary Jack Straw, comic actor and TV presenter Griff Rhys-Jones, author Douglas Adams (creator of Hitchiker's Guide to the Galaxy), fashion designer and style guru Hardy Amies, the journalist Peter Stothard, one of the youngest people to edit the Times, and the controversial historian David Irving.

Memories was invited to a Brentwood school reunion this month. The highlight was a lusty singing of the school song, which, a bit like the downpage verses of God Save the Queen, contrives to be both gory and sentimental at the same time. It begins with a man being burnt to death as an example to others. His remains were then left "for folks to see" alongside the elm tree that had acted as a stake. And we think things are rough on Essex streets today.

The man, or rather youth - he was just 19 - was William Hunter. His crime: simply reading a Bible in English.

One of the magistrates who condemned Hunter to death was a local squire, Sir Anthony Browne, of Weald Hall. In 1558, with a new monarch on the throne and a new religious order, Browne seems to have had second thoughts about that horrific execution, three years earlier.

Perhaps as a form of atonement, "good Sir Anthony" set up a school designed to instruct local boys in "virtue, learning and manners". The four words have remained the school motto to this day. Virtue was obviously a primary concern. One of the earliest school rules stipulated that pupils could be expelled for contracting syphilis.

Most of the buildings visible from the road are relatively modern. Tucked within the 70 acre site, however, is a remarkable survivor. This is the 1568 Old Big School building, a relic of Good Sir Anthony's original schoolhouse. Old Big School has been engulfed by other buildings, including an extension storey above. Yet from the school's beautiful gardens, it is still clearly visible for the marvel it is - one of the oldest purpose-built classrooms in Britain.

Visitors to the school's 450th anniversary exhibition, open to the public on saturday, will get a rare chance to see it.

Brentwood School is so brimming with history that it is easy to forget its greatest claim to respect, the open, modernising approach to education that has always characterised the way it does business.

Brentwood was a pioneer in the field of local scholarships, providing a first class education to local boys, regardless of their parents' means or social backgrounds.

The reforming tradition was personified in the figure of the great headmaster the Rev Edwin Bean. Bean had taught in Australia as a young man, and been impressed by the egalitarian approach. "The sons of judges and those of mechanics and tradesmen mixed on equal terms, with the best of results," he recalled.

Bean brought these principles to Brentwood to the consternation of some of his snottier colleagues. There is an hilarious account of Bean in 1913 "travelling by train with the headmaster of a leading public school, who whispered to him in awful tones, Is not Brentwood School becoming too democratised.?' " Indeed, it was.

That reactionary headmaster would have been even more appalled at today's school, where there is an amost 50-50 mix of boys and girls. While still concentrating on its original south Essex catchment area, Brentwood actively recruits from other European countries and from as far away as China. This is a forward looking school, but every 50 years it permits itself a wallow in its extraordinary history. Quite right too. William Hunter's old elm only perished in the early 1950s, proof, if needed, that strong roots give you staying power.