HE THINKS he’s Pooh Bear. That’s who Jonathan Watts, head of history at Benenden, one of the most famous gels’ schools in the country and alma mater to the Princess Royal, identifies with in literature. This means he’s solid, reliable and vulnerable. But not, of course, a bear of little brain who is gullible and gets things wrong. Now Watts is to break a 70-year-old tradition to become the school’s first male ‘housemistress’. The 43-year-old bachelor will take charge of 50 girls aged 11 to 16.

Benenden old girls range from the Princess Royal (‘We’re pleased when old girls do well,’ giggles Watts) to the BBC’s head of radio, Liz Forgan, and Baroness Ryder. It’s a £3,910-a-term establishment where they play lacrosse, have midnight feasts and parental Range Rovers disgorge tuck boxes and well-groomed ambitious young things for the tutelage of the indefatigably cheerful headmistress Gillian duCharme. Once comprised of daughters of the Empire, it is now full of daughters of solicitors, barristers and judges. The girls who normally parade in tatty jumpers and tights with holes in them are on holiday. Watts is sitting in the engraved-wood 19th century staff room where a 17th century dandy with cake-doily collar looks down from the wall.

Watts is chunky with receding hair, the look of a royal private detective, labrador enthusiasm combined with robustness, ingenuous charm and trustworthy voice. He’s keen on school dinners (particularly puddings) and school hols. He talks a lot, as do all teachers. He also has that actorly enunciation and projection that teachers go in for.

He’s wearing a suit, white shirt, squishy-soled shoes and rebellious tie. Before he arrived at the school five years ago, a friend said to him: ‘You’d better not wear a suit or grow a moustache or you’ll be mistaken for a housemistress.’

So is it true that the girls have nicknamed him ‘Sausage’ (on account of his generous girth) as reported in The Daily Telegraph? ‘No. They made that up. The girls tend to call us by our surnames, as if we were second undergardeners,’ he jokes. When the girls read the newspaper moniker they became protective. ‘Now you mustn’t get a complex and become anorexic,’ they said.

Watts is to become mother hen at Marshall House in September. He characterises Marshall girls as ‘independent, good organisers who get on with life and don’t get very emotional about things’. When Marshall girls win a coveted trophy there is ‘desultory applause’. Macmillan’s grandchildren, Lord and Lady Stockton’s daughters, are going there. Watts hopes to enthuse his charges with his passion for the double bass. He won’t parade round the dormitories (‘If I do, I’ll send a little girl ahead of me like a miner with a canary,’ he has said) or showers. But will he become a pin-up? Will the girls fancy him? ‘Oh come off it,’ he says, sitting with one foot on top of the other. ‘A balding, overweight school teacher!’ Unfortunately the former master who was a ‘crush’, a 24-year-old Jason Donovanish tanned classics teacher, left to become a rock star. So at Benenden now, ‘crushing’ often involves younger girls swapping gifts with older ones.

And how will this surrogate father deal with girly problems like premenstrual tension and pregnancy? ‘I have a full-time matron. But I’m totally unshockable. Beryl Reid said if someone were to tell her they were having an affair with a goat, her reply would be that she hoped it had nice eyes.’ And if a pupil came to Watts to say she was having an affair with a goat? ‘I’d probably ask to meet the goat and say, ‘I hope it’s clean.’ ‘ Unlike most people, Watts is genuinely fond of teenagers. ‘I like the things that infuriate other people, the faddishness. I lose track of the acned Australian pin-ups who appear on dorm walls. Often I get a little girl to give me a lesson in what’s going on. My bedtime reading is occasionally Just 17. You have to be able to empathise at this level.

‘You should be able to devote lots of time to drinking squash and eating inordinate numbers of chocolate biscuits. Then when something goes wrong they feel they can come to you. Many girls prefer to talk to a man (30 per cent of the Benenden staff are male). It also helps to remember what it was like when you were 15.’ What was it like? ‘I can’t remember . . . Well, it was a period of great self-doubt and uncertainty.’

His own education spanned local authority grammar school, choral scholar at Oxford and research work at York University where he produced one of the world’s many unwritten doctoral theses. ‘It sits in cardboard boxes at home. I’m not sure civilisation has lost much by its lack of information on English painting between 1390 and 1450. Occasionally I look at it and can’t understand it.’

Watts is of solid academic stock. His father is a retired primary school head, and his sister a slide librarian at Exeter University. Formerly head of history at two independent boys’ schools, Watts was appointed at Benenden after a 45-minute interview and tour of the grounds, 240 acres of Kent countryside. ‘The question which floored me completely was, ‘Why in five years time will we be pleased to have employed you?’ With a naturally English sense of masculine modesty, I refused to answer.’ (On being pressed, he said something about academic excellence and enthusiasm.) He treats women in egalitarian fashion. ‘I don’t think of them as feeble creatures who should be doing flower arranging.’ But he has mostly taught in boys’ schools. ‘Female students work harder, are more cautious, keener to get things right and don’t take risks,’ he concludes. ‘They tend to see what’s bad rather than good. They’ll come out of exams saying, ‘Oh my God, I didn’t know that,’ whereas boys will say, ‘Marvellous question on Henry VII.’ When you point out that it was on Henry VIII, they’ll say, ‘Oh what’s a number between friends?’’