Denis Beacham, who was head of the school between 1967 and 1984, prided himself on running a tight ship. In a school named after a dashing war hero, his boys were expected to be men, both on and off the rugger pitch.
"I said to them: 'don't whinge, don't moan, don't tell me you're tired. I'm tired too,'" said the 80-year-old former head. There are, Mr Beacham adds, many boys he remembers vividly. But Colin Firth is not among them. "He was a somewhat quiet, withdrawn boy, academically moderate. By and large, he passed through school without any colour at all. He made no impact on the school."
Instead, Firth took refuge among kindly members of staff. Angela Kirby, in particular, Mr Beacham says, thought the best of every pupil, while Arthur Newton was "a dear old English fuddy-duddy. He was a wonderful chap."
Ultimately, though, Mr Beacham believes that Firth would have been happier at a co-ed school. The type of boy who flourished at Monty would be unlikely to turn to acting in later life.
"One chap is a full commander of the navy now - he is commanding a nuclear submarine. I was told by his admiral, 'your lad has done damn well'.
"We have produced doctors, lawyers, barristers. But it's Colin Firth, Colin Firth, all the time, just because he's an actor."