Only four of the city's 13 sixth forms attract more than 100 pupils. Retention and achievement rates are well below comparable averages elsewhere, and total numbers, at just over 1,200, have dropped steadily since 1996.
The move reflects national trends, revealed in a recent TES FE Focus survey. While seven out of 10 schools expect to retain their sixth forms under changes in the Learning and Skills Act, most small and urban sixth forms have seen the writing on the wall.
In Lewisham, south London, four sixth forms, with a combined roll of 200, may be replaced by a new sixth-form centre.
Bristol's post-16 review discussion document, just launched by the local authority, considers five options of which total abolition is the most radical.
"Generally, sixth-form education in Bristol provides poor value for money and poor outcomes," the authority says. Any single replacement college would have to cater for up to 1,600 students.
Alternative schemes include building two smaller colleges, or retaining the twolargest sixth-forms at Cotham grammar and St Mary Redcliffe and building an additional college.
The LEA has also considered building five post-16 centres, or creating several 11-14 schools that would feed a smaller number of 14-19 colleges.
Despite strong differences of opinion, most agree that the status quo is untenable. "In the end, we come up with a different model from any of the five proposed," said Richard Riddell, the city's director of education.
"Our schools are about 25 per cent smaller than in places such as Birmingham and Manchester and it gives us a smaller critical mass in terms of sixth form. Some are just bumping along with 40-50 students."
After consultation with all stakeholders, formal proposals are due to go before the council next January. A decision will be taken in the summer term, to be implemented in 2002.
While heads with declining sixth forms may recognise the inevitability of closure, Chris Gardner at Ashton Park will be battling to save his. "We opened in 1999 with 63 students because we were dissatisfied with the quality of A-level provision in south Bristol," he said. "Now we have more than 120 and we will fight to the bitter end."