Martin Gillespie and Philip Littlejohn would be ordinary-looking teachers were it not for the little scarves tied around their middle-aged, Anglo-Saxon heads. Mr Gillespie's is blue and Mr Littlejohn's is white. While the casual onlooker might be a little distracted by their eccentric fashion accessories, these two intrepid veterans of the chalkface seem perfectly at ease with them. Happy, even.
At Guru Nanak primary and secondary schools, housed in a former Catholic school building in the borough of Hillingdon, west London, everyone wears something on their head. To be on the staff of the first and only Sikh schools in Europe to receive state funding, all teachers must agree to cover their heads in the building. With only two Sikh teachers between the two schools ("Shocking, isn't it?" laughs secondary school head Rajinder Singh Sandhu), that amounts to an awful lot of commitment to the job. On the other hand, it does put an end to bad hair days.
Women teachers have it a whole lot easier than the men, aesthetically speaking. Like the girl pupils, they wear long scarves and clothes that cover their arms and legs, as devout Muslims and Jews do. The girls wear the traditional dress shalwar kameez under their smart blue blazers, and scarves over their heads. Young boys cover their topknots with white cloth, while older ones wear turbans. (The topknot is worn because the Sikh religion forbids cutting the hair, and keeping it tied is more convenient than wearing it long.) For health and safety reasons, the children take their head coverings off for science and PE lessons.
In every other way, Guru Nanak primary and secondary are like any schools. Boys and girls charge up and down the stairs laughing and talking at breaktimes, playing sports as if their lives depended on it in PE and devouring impressive quantities of pizza and chips at lunchtime. There is no segregation of the sexes for any activity, and no problems with sex education - not a single child has been withdrawn.
But religion is embedded in the schools in a variety of ways. You'll find no meat, fish or eggs in the dinner hall, in keeping with Sikh dietary laws. Primary and secondary assemblies take place in the gurdwara, a vast carpeted room with portraits of the 10 gurus on the wall, where acts of worship are performed. All students study Punjabi up to GCSE level and secondary pupils have one hour a week of Sikh studies in addition to general religious education. Sikh studies can be taken at AS-level, and Punjabi is offered as an A-level.
The school day is long, from 8.30am to 4pm, to accommodate the half-hour assembly. On Fridays, school begins at 8am to make time for 30 minutes of exam practice and simulation for pupils taking national tests and GCSEs.
The Guru Nanak ethos emphasises Sikh values such as honesty, self-awareness, generosity, good citizenship and a respect for other faiths and cultures. The pupils are a hard-working lot, who get their reward in the shape of exam results. In 1998, 78 per cent achieved five or more A-C grades at GCSE (the average for Hillingdon was 44 per cent). The school is anticipating 80 per cent this year. All of its Year 11 students achieved A to C grade GCSEs in science. One girl is expected to achieve 10 A* grades, and is likely to follow in the footsteps of Sukhwinder Kaurrai, who in 1998 was the first Guru Nanak pupil to go up to Oxford, to do law.
The positive ethos is reflected in ways that go beyond academic achievement. Pupils are polite and respectful of other people and religions - RE classes focus on the major religions of the world. The national curriculum is taught as it would be anywhere else. Rajinder Singh Sandhu is adamant that the schools should reflect the outside world. "We don't teach from a Sikh perspective. We encourage pupils to be independent thinkers about their academic studies and their religion," he says.
Peter Reyerson, vice-chair of governors and a local councillor, says one of the first things that struck him about the schools was that "they are not dogmatic about religion". The staff are a mix of Christians and Muslims. The head of the primary school, Philip Littlejohn, is a Christian. Until recently there was also a Jewish teacher.
When you talk to pupils, it's clear that they want to learn about their own culture and religion, but that they see themselves as part of multicultural Britain. And they want to succeed. As 16-year-old Amrinder explains: "When our parents and grandparents came here, they were mainly working-class and had to work hard. Now they're financially secure, they want their children to get better jobs than they did. Indian parents encourage their children to work hard. Education is a driving force within our culture and our religion."
But why come to Guru Nanak instead of a secular school? Well, there's racism for a start. Surith, a Catholic Year 10 boy originally from Sri Lanka, says he was driven out of his former school - a highly sought-after grammar in west London - by racist bullying. "After all I've been through, this school has saved me. My former school did nothing about the bullying I was complaining about for three years. It was easier for the teachers to ignore it." At Guru Nanak, although he's the only Catholic pupil and one of only a dozen non-Sikh students in both schools, he feels at home. Bullying, according to pupils and staff, is unknown.
But parents are most attracted by the schools' high academic and moral standards. They see Guru Nanak as a sanctuary from the maelstrom of drugs, lax discipline and sexualised behaviour of other schools, as well as a place where their children can learn about their religion. One 13-year-old boy says: "The state schools in this area where a lot of Asians go aren't considered very good. Most people going to them don't go on to university."
But how do they square their desire to be part of the wider world with the insularity of attending a Sikh school? For Amrinder, there's no contradiction. "Because one of the main aspects of our religion is respecting other religions, when we go to university we'll have the confidence and understanding of other cultures."
Not surprisingly, the schools are hugely popular. The areas they straddle, Southall and Hayes, have big, well-established Asian communities.
Established in 1993 as the Guru Nanak Sikh college, the schools were run until last September as one private school for four to 18-year-olds. In the face of mounting financial difficulties and increasing demand from parents worried about standards in British mainstream schools, the college decided to apply for grant-maintained status, encouraged by the large number of Hillingdon secondary schools that had already opted out.
But this was the summer of 1997. Labour had just won the general election and the mood was swinging against grant-maintained status. The Department for Education and Employment advised the school that it should apply for voluntary-aided status instead. That proved difficult, as funding arrangements for voluntary-aided schools had lapsed.
Luckily, John McDonnell, the Labour MP for Hayes and Harlington, joined the campaign and proved an effective nobbler of ministers. Two years later the school's voluntary-aided status was finally approved. The official opening on November 30 last year was attended by the Home Secretary, Jack Straw.
The Conservative government made clear its disapproval of publicly funding minority-faith schools, an attitude exemplified by its refusal to grant voluntary-aided status to the Islamia school. The north London primary applied for state funding in 1986 but had to wait until January 1998 - and a Labour government - before it and another Muslim school, Al Furqan primary in Birmingham, became the first minority-religion schools in Britain to get state funding.
Education Secretary David Blunkett argues that including schools of other faiths within the public fold promotes cultural diversity in the state sector, offering parents more choice. "Diversity has increased in recent years," he says. "For a long time, governments resisted extending the voluntary aided sector. Yet not only do I believe we were right to welcome Sikh, Muslim and Seventh Day Adventist schools into the state sector, the decision to do so has been widely accepted.
Since coming to power, Labour has approved public funding of five other minority-faith schools (two Muslim, two orthodox Jewish and one Seventh Day Adventist), with others waiting in the wings.
But is growth in religious minority state schools really promoting cultural diversity or just creating education ghettos? Yasmin Alibhai-Brown of the Institute for Public Policy Research finds little to celebrate in Blunkett's approach. She wrote recently that the Government's actions signalled "the end of a dream which has yet to be dreamt... educating children to separate out from others the core values which should bind the various peoples of any national entity".
Other critics argue that giving state funding to religious schools is a way of ducking difficult decisions about racial and social inclusion. It is, they say, socially expedient.
But the Commission for Racial Equality argues that the Guru Nanak decision is "a step forward in creating fairness in public funding". The CRE rejects the argument that a school's denominational base "will necessarily conflict with the attempt to build a multicultural education system - as long as attention is paid to the curriculum, attitudes and entry requirements".
With Guru Nanak's transformation to state school has come its division into separate primary and secondary schools with rolls of 160 and 450 respectively.
The next phase involves doing something about the schools' building, which has definitely seen better days. Although the capital funding arrangements are yet to be agreed with the local authority, governors are already considering several possibilities. The most attractive involves selling the present site to developers and using the proceeds to build two new schools in another location.
This has become an important issue because the signs are that Guru Nanak primary and secondary are destined to be oversubscribed, with the Sikh burghers of west London clamouring to get their children into one of the top schools in the area - whatever its religious orientation.
What is Sikhism?
The Sikh religion is a monotheistic faith founded by Sri Guru Nanak Dev Ji (1469-1539). He was born in a village not far from Lahore in present-day Pakistan, at a time of Muslim-Hindu confrontation, when some were seeking a reconciling truth.
It is said that after disappearing for three days from his home, he returned and said: "There is neither Hindu nor Muslim. so whose path shall Ifollow? I shall follow God's path."
He did not attempt to merge Hinduism and Islam, but believed that God lay beyond religious systems and rituals (it must seem ironic that his own work resulted in the development of yet another religion), and based his new doctrine on simple living, piety, monotheism, opposition to idolatry and magic, and equality of all believers - men and women - before the transcendant god. Community service was highly valued.
He was succeeded by nine more gurus, who helped develop the teachings contained in the Sikh Scriptures, the Guru Granth Sahib.
Sikhs have no weekly holy day. They should go regularly to the gurdwara to pray and read from the Guru Granth Sahib, but much of their daily worship and meditation takes place in the home.
There are more than 20 million Sikhs worldwide.