The Church of England today voted overwhelmingly in favour of banning clergy from belonging to the British National Party .

On the second day of the General Synod, the legislative body that meets twice a year, more than 300 of the 418 members gathered in Westminster endorsed a motion asking the House of Bishops to keep BNP members out of the church.

The members wanted a policy similar to that adopted by the Association of Chief Police Officers, which bars police from belonging to an organisation that "contradicts the general duty to promote race equality".

The House of Bishops is now obliged to draw up and implement the policy, and needs to decide whether any change in the church's present laws is necessary or desirable.

In a 90-minute debate, Vasantha Gnanadoss, who proposed the motion and is one of a handful of ethnic minority synod members, said: "My personal experience is that the church is institutionally reluctant to take any bold measures related to racism.

"Passing this motion is a push that is seriously necessary. Without it, the day may come when the BNP will have gained significant power and the church will stand accused of having been feeble when it could have been resolute."

The motion received support from the archbishop of York, Dr John Sentamu, and the archbishop of Canterbury, Dr Rowan Williams.

Another synod member, the Rev Rose Hudson Wilkins, said: "We know these [racist] views exist here. Why are there so few people from ethnic minorities sitting in this chamber? There are racist undertones in parishes and dioceses.

"We're all being nice and friendly. The undertones are there. We are kidding ourselves if it comes from somewhere else."

There was a perception, she added, that people from ethnic minorities had nothing to contribute to the life of the church.

Others commented on the overwhelmingly white nature of the synod and suggested that a strong statement against racism could have a positive effect on the Church of England's makeup.

According to the latest church statistics, only 2.8% of its 114 bishops and 1.4% of the 4,443 priests come from ethnic minorities.

The Rev Canon Simon Killwick said: "Ethnic minorities are scandalously under-represented in our clergy. Let's see an increase in their recruitment."

There were attempts to stymie the proposal and dilute it, by removing references to the ACPO policy and the BNP, but these changes found little support. The bishop of Rochester, Michael Nazir-Ali, voted in favour of one such amendment.

William Fittall, secretary general of the synod, warned that there may be legal difficulties in implementing the policy. In a background paper, he said clergy could not currently be disciplined for lawful political activity, and the BNP was not a proscribed political party. He suggested the church could be vulnerable to discrimination claims.

The synod also heard a presidential address from Dr Williams, who reflected on the nature of debates to come, namely tomorrow's discussions on legislation approving the ordination of women as bishops.

He told the chamber that neither those supporting nor those opposing the historic change were unlikely to disappear.

"They want to be part of the family still. And that means that some dreams of purity and clarity are not going to be realised.

"Both [sides] have turned their backs on the fantasy of a church that is pure in their own terms, in favour of a church that is honest about its diversity – even when that diversity seems at first embarassing and unwelcome."

In tomorrow's debate, which is scheduled to last three and a half hours, the synod will vote on whether to send the draft legislation to a revision committee or leave it unchanged.