Image copyright PA Image caption General synod members will vote on an amendment to the Church's disciplinary measures

The Church of England's ruling synod is expected to ban clergy and church workers from belonging to organisations such as the British National Party.

Clergy would be prevented from expressing support for groups the Church considers racially prejudiced.

Supporters say the proposals could bring more racial diversity to a predominantly white Church clergy.

General Synod members meeting in York will be asked to vote on an amendment to the Church's disciplinary measures.

This would make it "unbecoming" or "inappropriate" conduct for clergy to be members of a political party with policies and activities declared "incompatible" with Church teaching on race equality.

Under the proposals, Church of England bishops would decide which parties or organisations this applied to.

Vasanatha Gnanadoss, a Metropolitan Police civilian worker and General Synod member, first won support for the move three years ago.

The synod, which is meeting for four days at York University, has already backed sending legislation on women bishops to a final vote on Monday.

Women now constitute a third of priests and there is a widespread feeling among Anglicans that the role of bishop should be open to them.

But plans to exempt traditionalists from serving under women bishops have caused division within the Church.

The synod could also opt to adjourn the debate further to allow amendments made to the proposal in May to be reconsidered.

Any adjournment would delay a final vote until November at the earliest. A defeat would mean the appointment of women bishops would be at least another five years away.

The synod needs a two-thirds majority in all three of its houses of bishops, clergy and laity.

If approved there, it would be sent to Parliament for approval and Royal Assent. The earliest likely date for a woman bishop to be appointed would be 2014.