Two senior councillors have accused their own party leadership of coercing politicians before a crunch vote on hugely controversial transport plans.

Veteran politician Ian Dewey and colleague Martin Veal have joined three opposition Liberal Democrat councillors in a highly unusual official complaint against the Tory cabinet which has run the Guildhall for the last two years.

Cllr Veal has quit as whip of the 31-strong Tory group on B&NES - a role which saw him having to persuade others to toe the party line.

The most serious complaint is that a Tory councillor who normally sits on the council's development control committee was replaced at last month's crucial meeting on the Bath Transportation Package - allegedly because of fears that he might oppose the schemes.

In his resignation letter, Cllr Veal says the leadership has "not acted in a manner consistent with the democratic principles of fairness, transparency and honesty."

The meeting voted nine to three to approve in principle a 1,400-space park and ride scheme at Bathampton Meadows, in the Bathavon North seat represented by the two Conservatives.

At the meeting which took the decision - which has been referred to the Government Office for the South West because the scheme is not mentioned in the local plan blueprint, committee member Cllr Malcolm Lees (Con, Weston) was replaced by Keynsham politician Cllr Brian Simmons (Con, Keynsham North).

Cllr Lees was available for the meeting and in fact sat through much of the proceedings until asked to leave by a council official.

A seven-page letter to GoSW director Jon Bright and new Communities Secretary John Denham says that this matter will also be at the centre of an official complaint to the council's standards committee.

It also claims:

* councillors were "pressurised, encouraged or coerced into voting in favour of the applications against their conscience."

* Cllr Simmons was called on "at the last moment" and had not read the reports by planning officials, or been on fact-finding site visits

* another councillor was "instructed as to how to vote and the consequences of not doing so were outlined."

The letter, signed by the two Tories and Liberal Democrat Cllrs Caroline Roberts, Loraine Morgan-Brinkhurst and Gerry Curran, also complains about misleading material in council documents, consultants' reports being kept secret and inaccurate meeting minutes.

It says: "Trust in our country's democratic system is at an all-time low. It is at times like these that we in local government need to be seen to be acting fairly and representing the interests of the people we represent.

"A process which is so fundamentally flawed cannot be allowed to stand."

The letter calls for new planning applications to be submitted relating to the package, which also includes the Bus Rapid Transit scheme through Newbridge and which would be funded by around £50 million of Government money.

It goes on: "In the rush to gain central Government funding, we firmly believe that the democratic principles of fairness, transparency and honesty have been abused."

The letter calls for Mr Denham and GoSW to reject both the meadows scheme and the BRT application, a decision on which was deferred at last month's meeting and which Government officials have already said they want to examine.

There are strict national and local guidelines about the way councillors should deal with planning applications, aimed at ensuring development control committee members go into meetings with an open mind and arrive at decisions based on the evidence presented there.

Council leader Cllr Francine Haeberling was unavailable this week but a spokesman for the Conservative group issued a statement on behalf of deputy leader Cllr Malcolm Hanney.

It said: "He advises that he has had no involvement with the planning process related to the Bath Transportation Package.

"He does, however, point out that the council's position related to the BTP was clearly set out and agreed by the council at last November's council meeting.

"In this respect, he notes that members of the council are quite free to express their views on the planning merits of any application in the light of relevant council policy to other members, whether related to development control or otherwise. Any member who takes part in decisions related to development control should take due account of all related planning matters, relevant council policy and other matters germane to any application being considered and should not come to the meeting with predetermined views."

The statement failed to explain why Cllr Lees was replaced, and Cllr Hanney said he was not in a position to comment on this.

Both Cllr Lees and Cllr Simmons have declined to comment on the matter.

Cllr Simmons assists the transport cabinet member driving through the transport plans, Cllr Charles Gerrish, in his role as cabinet associate for customer services.

But Conservative sources have pointed out that voting at the meeting did not divide along party lines and that if Cllr Lees was opposed to the BTP, there was an equal argument for him having to stand down to avoid accusations of bias.

The committee on the day was made up of six Tories - including chairman Cllr Les Kew, four Liberal Democrats and two Labour members.

The letter is given added weight by the fact that three of the five - Cllrs Dewey, Curran and Morgan-Brinkhurst - have served as chair of B&NES, and between them they have decades of experience of local government.

Cllr Curran (Lib Dem, Twerton), who is his party's planning spokesman, said: "The way the committee was conducted did nothing for the reputation of the council. In my opinion, it brought that reputation into disrepute in the eyes of the public. People did not see the committee process as having been fair, open and honest and many are of the opinion that some members were predetermined in their view on the applications.

"The council needs to be seen to be fair, open and honest. It has failed on this occasion."

Cllr Caroline Roberts, whose Newbridge seat is at the centre of the BRT scheme, said she was "appalled" by the decision process.

"Members of the planning committee should be fully briefed, should have visited the sites and should be aware of all the relevant information.

"At a time when public confidence in some politicians is at an all-time low it is a shame that some members have taken the actions they did in this planning process."

Her ward colleague Cllr Morgan-Brinkhurst said: "There has been a catalogue of procedural failings since the inception of the Bath Transportation Package, most significantly the attempts to manage the decision of the planning committee on the 20th May; we will be making a separate complaint to the Standards Board on this matter.

"We are not trying to stop the Bath Transportation Package in its entirety, but rather we are calling for new individual applications to be submitted to allow a proper democratic and transparent process to take place."

Cllr Veal, who is in France on a twinning visit, has been a B&NES councillor for nine years and also chairs a watchdog scrutiny committee.