There are a host of organisations running academies and independent schools in the UK. David Marley looks at the major ones
COULD MAKE A PROFIT
Global Education Management Systems (Gems)
Nationality: United Arab Emirates
Schools: runs 67 worldwide, including 12 private schools in the UK. Hopes to open 200 in Britain
Gems is one of the world's biggest education companies, with more than 70,000 students from 124 countries attending its schools. It has said it wants to operate as many as 200 in Britain, although Tayeb Chakera, its UK chief operating officer, admits that is a very long-term goal.
The company's plans to sponsor its first academy in Milton Keynes were scrapped after parents criticised one of its nearby private schools. But Mr Chakera said the company is still considering academy sponsorship.
Schools: 44 independent schools in the UK and 4 international schools
Led by Chris Woodhead, the former chief inspector of schools, Cognita is the biggest for-profit company running independent schools in the UK. Set up in 2004 with private equity money, its fees are lower than those typically found in the independent sector.
Mr Woodhead is famed for championing basic numeracy and literacy and traditional subject-based teaching. He has also spoken of his backing for a voucher scheme or tax credits that would let parents spend their child's state education funding at schools such as his.
Schools: around 100 state-funded US charter schools; consultant to 50 schools in England and manages one
The US company was the first to stir the idea of privatised state schools in the UK nearly a decade ago when it was suggested that its charter school model could work on this side of the Atlantic.
Its UK subsidiary has stuck to selling management services, and it is leading Salisbury School in north London in a million three-year deal worth pound;1m.
The Edison philosophy involves tough discipline and a reward system with prizes for good behaviour.
Mark Logan, Edison's UK managing director, said: "We are taking a very long-term view on this. "Markets change because people who show they can do a good job in one area tend to be offered more responsibility. The market evolves."
OPERATING AS CHARITIES
Girls' Day School Trust (GDST)
Schools: 28 independent schools and an academy in England; two international schools planned
The trust is the biggest charitable provider of education in the country. Set up in 1872, it now has around 20,000 pupils and 3,500 staff.
The Belvedere Academy in Liverpool, a GDST school, was one of the first two independent schools to become an academy in September last year. Birkenhead High School in the Wirral is due to open as one next year.
Barbara Harrison, the trust's chief executive, plans to launch an exchange scheme so staff can work in both private and state sectors.
Steiner Waldorf Schools
Nationality: British, but based on the principles of an Austrian educator
Schools: 25 independent schools in England, with its first academy opening in September
Steiner schools are known for their alternative approach to education, which focuses on the holistic development of the child. Significant portions of the timetable are given over to the pursuit of arts, crafts and dance.
There is no national testing regime in independent Steiner schools and pupils typically only take a small number of GCSEs.
The first Steiner academy will open in September when the Hereford Waldorf School in the village of Much Dewchurch, near Hereford, joins the state system. The Government has agreed that it will not have to follow the national curriculum.
United Learning Trust
Schools: 13 academies; two more planned
The trust is the UK's largest sponsor of academies, opening its first in Manchester's notorious Moss Side.
The Christian charity is a subsidiary of the United Church Schools Trust, which has been running schools in the independent sector for 125 years.
It also sponsors William Hulme's Grammar School in Manchester, one of the first two independent schools to become an academy in September last year.
All staff at the trust's academies are offered masters courses at Warwick and Sheffield Hallam universities.
School: three academies; six more due to open this September
Oasis is set to become the second biggest academy sponsor from this September, when it will be running nine schools.
Steve Chalke, its founder, is a committed Christian. He describes his schools as fully inclusive and the centre of the communities they serve.
While his faith was the motivation behind establishing Oasis, Mr Chalke insists that his schools do not select on the basis of faith or ability.
In the area around one of its schools in Enfield, north London, Oasis is running youth clubs and is building a new health centre with the local Primary Care Trust.
Nationality: British-based, founded by a Swiss businessman
Schools: three academies; five more planned
Ark is an international charity, based in London, that backs a range of education and health projects for children.
Arpad Busson, Ark's founder, is a Swiss hedge-fund manager.
The charity intended to break up its academies into smaller schools-within-schools, but this has taken longer to achieve than expected.
Sir Michael Wilshaw is Ark's education director. He is also headteacher of the highly regarded Mossbourne Academy in Hackney, east London, although this is not an Ark school. He has a strict approach to discipline.