Sixth-form colleges in England could soon be “consigned to history” because of overwhelming financial pressures and growing competition from schools, it has been claimed.

David Igoe, chief executive of the Sixth Form Colleges Association, said that colleges were at a “significant” financial disadvantage compared with other institutions because of additional costs and lower per-pupil funding. As a result, they were being left to “wither on the vine” by the government, he said.

The association is carrying out a survey to assess the full extent of the problem, but Mr Igoe told TES that about 30 of England’s 93 remaining sixth-form colleges could find themselves with budget deficits within the next two years.

This is because, unlike schools, academies and free schools, sixth-form colleges do not get a rebate on the VAT they pay on purchases, something which costs the average college an estimated pound;300,000 a year. In addition to this, post-16 students attract less government funding than 11-16 students but schools are able to subsidise them from their overall budgets.

Speaking at a Westminster Education Forum conference in London last week, Mr Igoe told delegates that the future of sixth-form colleges was at risk.

“Our fear is that we are writing the last chapter of a story that could soon be confined to the history section of English educational provision,” he said. The association had stepped up its lobbying efforts to persuade the government to create a “fair and equitable” funding system, he added.

“Sixth-form colleges are being squeezed financially more than any other provider,” he told TES. “We need a level playing field. We have got a really high-performing, highly efficient system - 89.1 per cent of sixth-form colleges are rated good or outstanding by Ofsted - yet for whatever reason we are going to be allowed to wither on the vine.”

Colleges that found themselves in the red could be issued with notice to improve from the Education Funding Agency, but they were given no help to draw up or implement a recovery plan, Mr Igoe added.

Unlike academies and maintained schools, colleges have no financial safety net. Some 32 sixth-form colleges have been forced to close in the past 20 years, most of which were small institutions that folded under financial pressure. Only three new colleges have opened in the same period. The most recent closure was Ludlow College, one of the country’s smallest, which merged with Herefordshire College of Technology in 2012.

By comparison, 138 new school sixth-forms have been established in the past two decades, as well as nine free schools with sixth forms. A further four are due to open later this year.

Mr Igoe said it was now almost impossible to open new sixth-form colleges. “Traditionally, if there was a demographic need for new post-16 provision in a certain area, there was a competition with various organisations bidding for funding. Since 2010 the only mechanism has been for free schools.

“These new providers are funded for two years on their estimated numbers, putting them at a significant financial advantage. If a sixth-form college fails, there is a duty to ensure provision is replaced, which is to the advantage of local schools and colleges.”

The first sixth-form college set up under the free school programme was the London Academy of Excellence (LAE) in Newham, established in 2012. Its headmaster Robert Wilne said there was no conflict between the two systems.

“You can’t make the blanket statement that free school sixth forms are in competition with existing sixth-form colleges,” he said. “If the demand is there, as it was in Newham, then free schools can respond to that demand.”

Although the LAE could claim back VAT, Mr Wilne stressed that it still faced many of the same financial pressures.

A spokesman for the Department for Education said the government had ended the historic funding difference between post-16 schools and colleges by putting both on the same rate.

“We have also implemented the recommendations made by Professor Alison Wolf [in her 2011 report on vocational education] that funding should be on a fair per-student basis, not per qualification. This ensures that young people are studying high-quality qualifications that will help them get on in life,” he said.

“At the same time, we have put in place protection funding until 2016 so all colleges and sixth-form schools can continue to make the same offer as before.

“Free school sixth forms are funded on exactly the same per-pupil basis as other sixth forms and any suggestion that they are funded preferentially is false.”