A leader of a prominent evangelical grouping in the Anglican war over gays has been appointed bishop to one of the oldest historic Episcopal seats in the country.

Although Sherborne, founded in 705, is no longer a see in its own right but an area in the Salisbury diocese covering Dorset, the appointment Dr Graham Kings as its bishop is one of the strongest signs yet that the Archbishop of Canterbury is winning the battle for Anglican unity.

Dr Kings is founder of the increasingly influential group Fulcrum, which publishes the writings of conservative evangelical Bishop of Durham, Dr Tom Wright.

Fulcrum, based at Dr Kings’ present church of St Mary’s Islington, has campaigned for orthodoxy without schism in the Church of England.

Fulcrum is aligned theologically with conservatives in North America who are also attempting to maintain a conservative agenda without schism.

Unlike other conservative bishops, clergy and laity who have already left, the centrist conservatives are resisting moves to defect over the consecration of a gay bishop and the blessing of same-sex marriages.

Fifteen of these bishops in The US Episcopal Church, who belong to the Anglican Communion Institute, this week published a statement arguing for the recognition of the individual diocese as “church” rather than the national province.

If these were accepted, it would mean that dioceses could individually sign up to the new unity document, the Anglican Covenant, even if a national church refused to do so because it wished to pursue a more liberal pro-gay agenda.

Dr Kings said he believed the strategy of Dr Rowan Williams to attempt to keep most conservatives and liberals on board through the “covenant process” was working.

The issue will come to a head once more this summer when The Episcopal Church, which precipitated the crisis with the consecration of Gene Robinson as Bishop of New Hampshire, holds its three-yearly General Convention in California.

Dr Williams will attend the convention, which takes place in July, immediately before the Church of England’s own General Synod in York.

In the name of unity of the worldwide Anglican Communion, conservatives will resist any attempt to get The Episcopal Church to row back on its commitment to hold fire on same-sex blessings and consecrations of any more openly gay bishops.

Dr Kings said: “The whole strategy of the covenant is working.”

He said Dr Williams had succeeded in uniting the 39 Primates or Archbishops of the worldwide church at their recent meeting in Alexandria. “There has been a huge change,” he said, adding that conservative bishops were no longer speaking of finding an alternative centre of Anglican unity other than Canterbury.

The Bishop of Salisbury, Dr David Stancliffe, himself a leader of the liberal Anglo-Catholic movement, Affirming Catholicism, said Dr Kings would “bring vigour and insight” to the task of mission in the diocese.

Dr Kings, 55, married with three grown-up children, succeeds Bishop Tim Thornton who became Bishop of Truro last year. In 1999 he raised funds for nomads in Kenya by leading a walk from Oxford to Cambridge with a camel.