Staff at KIPP Academy described how unions had filed a grievance against the school without the solicitation or consent of the teachers, who were forced to issue a statement which pointed out that in their view this union's action could "compromise the strong environment of communication and collaboration that is integral to the success of our schools". 

A recent film, The Lottery, documented the difficulties faced by another successful charter school, Harlem Success Academy. The school, which has won widespread praise for its incredible performance in an area of long-term education failure, was blocked from moving into new premises by a union-backed lawsuit. At public hearings the school's founder was subjected to remarkable levels of abuse from union-organised campaign groups and from elected politicians allied to them. She admits on film that she has even faced death threats, all because she wanted to expand a school which has been improving the life chances of local children. 

KIPP schools have been forced to respond to this opposition. KIPP Academy's staff filed for the union to be decertified as their negotiating representative and staff at KIPP AMP Academy Brooklyn have also voted to cut union ties. Reform-minded politicians are beginning to heed the advice of the former New York schools chancellor, Joel Klein, and take on the education establishment. Governor Chris Christie of New Jersey condemned their "political thuggery". Washington DC's former schools chancellor, Michelle Rhee, last year successfully overhauled tenure laws, introduced merit pay and fired incompetent teachers. This robust response is, in Klein's view, the only response since "collaboration is the elixir of the status quo crowd". 

Last month, the first of 24 free schools opened in England. Like charters, they are state-funded but independent of local authority control and regulations, and are beginning to evoke the same kind of opposition from the education establishment. 

The government has already enabled existing schools or their replacements to convert to academies, giving them the same freedoms as free schools. So many have taken advantage of this that their opponents have had no time to mobilise. With more than 1,000 academies now established (including nearly 40 per cent of secondary schools), the Education Secretary Michael Gove's goal of making academy status "the norm" will soon be a reality.