A plan to end free bus journeys to religious schools in Hertfordshire has been approved despite furious opposition and a large demonstration.

The proposal, criticised as an attack on faith and a breach of trust, was voted through at Tuesday's full meeting of Hertfordshire County Council, picketed by hundreds of objectors including prominent religious leaders.

Roman Catholic Bishop James O'Brien told protestors gathered outside Hertford's County Hall: "Faith schools should be defended, not marginalised, reduced and deprived of support."

The Anglican Bishop of Hertford, Christopher Foster, said: "There is no real choice if it depends on ability to pay."

Borehamwood councillor Frank Ward, who described the plan as an evil and iniquitous proposal from anti-God forces', said it could be challenged by a judicial review.

Mr Ward founded the South Herts Faith Defence Movement to fight the proposals.

Inside the council chamber, the Tory cabinet's proposal to phase out the current entitlement to free denominational home to school transport was opposed by Labour and Liberal Democrat members.

Lib Dem leader Chris White warned it could lead to the closure of schools in St Albans, such as Townsend C of E and Nicholas Breakspear Roman Catholic, which are attended by many children from the Borehamwood area.

He told his Conservative opponents: "Sectarianism is not something which usually occurs in Hertfordshire, but you have stirred it up, and you should be ashamed of that.

"This is a terrible mistake we are about to make."

Councillor David Lloyd, the responsible cabinet member, said the plan had been watered down to allow free bus journeys for families with a combined gross income of less than £14,155. Children whose siblings are already at faith schools if their school is over the statutory walking distance more than two miles for children under eight and more than three miles for those over eight will also be exempt.

The move will save £2.5 million annually, although not for several years as free travel will continue for all those who currently receive it.

Mr Lloyd said: "Is it right that two per cent of school children across the county get £3.5m, a third of all the budget for school travel, spent on them?"

County Councillor for Borehamwood John Metcalf, who voted against free transport for faith schools, said he wanted to see a fair transport policy implemented.

"We looked at the possibility of having free transport for all children but this was ruled out on cost grounds.

"Now we are looking at providing free transport for the low income groups across the board and are hoping that Government legislation will bring this in.

"The fairest thing was to phase out free transport for denominational schools only."

But critics said the move would cause extra traffic, with parents driving their children because they could not afford the bus fare, which could be as high as £500 a year.

Labour's education spokesman Tanis Kent said: "A school that teaches the value of your faith is very important and special to parents.

Supporters of religious schools argue that churches have spent considerable sums on them in the understanding that the county council would fund free transport.

Labour tabled an amendment to delay the move to September 2008, while a Lib Dem motion proposed to withdraw it completely. Both were voted down and the Tory proposal was approved by 40 votes to 29.

Although most councillors voted with their parties, there were exceptions, such as Bushey Tory Seamus Quilty and Labour member Mr Metcalf.