Benedictine monasteries have been bastions of teaching and scholarship for centuries and their schools bastions of single-sex education. But this term marks a seismic shift for the UK Benedictine community because the monks of Ealing Abbey have voted to admit girls into their school. The decision to make the 800-strong St Benedict’s fully co-educational from 2007 - girls have been admitted to the sixth form since the early 1970s - marks the end of the only Benedictine boys’ day school in the country and follows the shift of Ampleforth Abbey and College, one of Europe’s largest Benedictine monasteries, which has been co-educational for two years. Both communities say they accept that if the Roman Catholic church and its schools are to thrive in the 21st century then men and women, boys and girls, must work side by side throughout their lives.

St Benedict’s lay headteacher Christopher Cleugh took over in 2002 as a committed co-educationist despite having previously been head of boys’

Catholic schools in Liverpool. “If boys and girls are educated together they are much more likely to understand each other, to know what makes each other tick, and that will help,” he says. “It is important for working and family life. I believe that in years to come there won’t be a single-sex Catholic school left.”

The Catholic church faces an uphill task in re-establishing trust after its child abuse scandals. And some people question whether monasteries, which seem male institutions far removed from societal pressures, can educate girls effectively. But Benedictine monastic bodies have changed significantly. Where monks would once have been old boys straight from school, they now join from other walks of life, often in their mid-30s and 40s. Teachers are largely lay and although monks retain senior positions in both schools and act as chaplains, they are familiar with life beyond the monastery walls. The schools also believe their pastoral care as well as spiritual life are strengthened by co-education.

Father Gabriel Everitt, the monk headteacher of Ampleforth who has led the introduction of co-education, knows something about the switch from all-male to co-education environment having been a doctoral student at Balliol College, Oxford, when women were taken in for the first time. “We had a sense that it was totally the right thing to happen, the nature of the times. This is also the feeling at Ampleforth,” he says.

For Ampleforth, a pound;22,000-a-year school of 600 pupils on the edge of the North Yorkshire moors, it also means boarding places are now full. More than 20 per cent of pupils are girls, a proportion expected to rise to between 30 and 40 per cent by 2010. For St Benedict’s in London, which faces stiff competition from high-achieving local Catholic state schools such as Cardinal Vaughan and the London Oratory and whose Catholic intake is down to 50 per cent, it may mean a higher percentage of Catholic pupils.

In a school where rugby sometimes seems to be the first religion - it boasts junior rugby internationals in its sixth form - 80 per cent of the parent body nevertheless expressed support for co-education.

Mr Cleugh is determined that girls will not be second-class citizens in his school. “I don’t intend St Benedict’s to be a boys’ school that takes in girls. What we will be teaching is a way of living that is enriching for boys and girls working together. Religious orders give stability to a school, they provide an extra witness to the world, an extended notion of family and community and give young people values that they can take throughout life.”

Father Gabriel agrees. A convert to Catholicism who once worked as an Anglican priest in Hartlepool, he believes that by adapting the Benedictine Rule, laid down in the sixth century, he is able “to provide a model for daily living” in a 21st-century co-educational school. Respect for one another and humility are at its heart, he says - not the “bland, Blairite variety” but “finding God in people as Benedict did”. He believes that the monastic rhythm of daily prayer and office “offers space for reflection in a busy school” and that monastic vows of stability (putting down roots); conversion of life (the stimulus to grow and change, for each day to provide a fresh start); obedience (a culture of listening and “well-timed”

and patient dialogue “when things aren’t going too well”) can be adapted to a community of male and female adolescents.

Katy Kallagher, 15, one of Ampleforth’s first fully co-educational intake, says the strong sense of community in the monastery is echoed in the life of the school. “As girls we don’t feel we’re in a minority; you are accepted for what you are and everyone is open and fair.”

The Benedictines’ decision is bolstered by research which shows that single-sex education does not advantage boys or girls. In one of the most comprehensive studies of the way children learn, Alan Smithers, professor of education at Buckingham University, finds that a century of research “has not shown any dramatic or consistent advantages for single-sex education”. If single-sex schools do better in league tables, he says, it is due to selection and social intake. The number of single-sex state schools has fallen from nearly 2,500 to just over 400 in 40 years.