Dr Kevin Stannard, director of innovation and learning at the Girls’ Day School Trust, writes:

The Independent Schools Council (ISC) recently entered into the general election spirit with its 2015 Manifesto. Strikingly, the manifesto asserts: “The strength of our schools lies in their very independence”. But independence is a double-edged sword. Independent schools have freedom, but freedom from what? And in opting out of elements of a national framework, what precisely is the alternative framework that they are choosing instead? It behoves those who declare independence to explain precisely what they are asserting independence of. In nation-state terms, there is a thin line beyond which lies separatism - with often very negative connotations.

“Positive” independence means defining clearly what you stand for, rather than what you are against. More than that, it should not entail isolationism, but rather a commitment to articulating a vision and engaging in debate, modelling initiatives and seeking to sponsor and spread good practice.

One attraction of independence is the ability to mitigate the unsettling impact of the frequent and abrupt movement of goalposts, and even outright policy reversals, which have bedevilled education in England in recent decades. Remember the false dawn of diplomas? The current A-level reforms are a direct result of the systemic problems that were created by Curriculum 2000, which was in its turn the reasoned response to the crisis that by the late 1990s threatened to overwhelm the original A-level model. Moreover, the move to IGCSE was at least in part a response to the perceived modularisation of GCSE, the clerical marking and the increasing amount of coursework and controlled assessment in the national qualification. Before 2010, IGCSE was the exclusive preserve of independent schools.

Independent schools almost by definition cannot speak or act as one - nor are individual schools necessarily consistent in their own messages. In the early 2000s, reaction to the modularisation of A-level and the introduction of the AS-level led a number of such schools to champion Cambridge Pre-U as a fully linear alternative. Oddly, the threatened return of A-level to linearity has provoked a pro-AS response from quite a few independent schools, some of which seem to be thinking about International A-levels as a refuge, in which AS-levels still count towards the full qualification.

Independence might in fact be seen, on closer inspection, as something of a chimera. Schools that stand proudly outside the national curriculum and are proud to languish at the foot of Department for Education performance tables are, quite rightly, still bound by statutory regulations around safeguarding, and by the ever-growing requirements of the Independent Schools Standards Regulations and the inspection regime that it mandates.

The ISC Manifesto asserts the right of independent schools to choose their own curricula and qualifications, but the constraints around this are both tight and obvious. The “end-users” - universities included - of qualifications, exert a strong influence. As of course do parents, whose understandable anxieties and demands are not necessarily in step with schools’ visions of autonomy.

Independence cannot and must not entail separatism. Cross-sector partnerships benefit all concerned, as was evident at Putney High School’s Women in Leadership (WiLpower) day in February. Working alongside Year 10 and 11 girls from a neighbouring state secondary, St John Bosco, the one-day event celebrated all aspects of women in leadership. Eight girls (four from each school) devised the format of the day, which included workshops and performances on subjects such as confidence-building, career-planning and the importance of personal and professional support networks.

The ISC Manifesto rightly points out the many ways in which independent schools engage with and serve their local communities by sharing best practice. But engagement is a two-way street, and excellence is far from the exclusive preserve of independent schools.

Participants in teaching school alliances know this. The Girls’ Day School Trust, as a network of fee-charging schools and academies, benefits from such cross-sector dialogue, including for instance the Driving Outstanding Practice programme, which brought together colleagues from schools and academies in the North of England. The use of data in monitoring and maximising pupil progress is something that state-maintained schools have much to teach colleagues in the independent sector.

Independent schools often have the space and the resources to innovate and excel, to try out new things and even to take risks, but they have the responsibility to anchor their initiatives in research, and share their learning across the educational community. Increasing numbers of independent schools are appointing research leads to coordinate such work.

The greatest challenge for the independent school sector, and for those to whom the ISC Manifesto is addressed, is in fact not mentioned explicitly in that document. It is how to balance the virtues of independence with the dangers of separatism. Independent schools might gain in the short term from a widening gap with the rest of the school sector, but in the long run such a lacuna benefits no one. Independent schools should resist any policies that threaten (even as an unintended consequence) to widen the divide.

Exam reforms fall exactly into this territory. The removal of IGCSEs from DfE performance tables is unlikely to change independent school curricula, but it forces state schools back into line and divides the sector. The argument over modular-versus-linear at A-level involves those on both sides making the same assumption - that one size fits all. The decoupling of AS from A-level makes sense to many who deal with pupils destined for academic courses at selective universities. But there are many young people for whom a modular approach would make more sense. Schools should have the right to choose the most appropriate routes for their students. But all schools should have this right, not just independent ones. Current policies propose divisiveness, and it is a widening divide, not the existence of an independent sector, that threatens to undercut progress in English education.