The Archbishop of Canterbury is being urged by a clerical abuse survivor to abandon the Church's insurer in the wake of a scandal over its 'derisory and heartless' treatment of victims.

It comes after three bishops urged the Ecclesiastical Insurance Group (EIG) to review a settlement of £35,000 that was offered to Gilo, whose surname is withheld to protect his identity, saying they were 'very concerned about the way in which the claim was handled at the time'.

The Bishop of Durham, Paul Butler, the Bishop at Lambeth, Tim Thornton, and the Bishop of Buckingham, Alan Wilson, expressed their concern that 'horse-trading' between lawyers about settlement figures had 'little concern for the impact' on the survivor.

Now Gilo is urging the Archbishop of Canterbury, Justin Welby, to review the settlement offers made by EIG to abuse survivors and relieve the company of its responsibility to reach settlements.

'The way the Church and its insurers has treated survivors institutionally compounds the abuse we have already suffered,' he wrote in the letter to Welby.

Gilo said he suffers from long-term bi-polar disorder and long periods of severe illness as a result of the abuse he suffered at the hands of Garth Moore in the 1970s. Gilo told numerous figures within the Church, including three bishops, of his abuse over a period of four decades but none of the senior figures he told say they have any recollection of his disclosures and no records were kept.

'The effect on my quality of life and relationships has been substantial,' he said. 'And despite being reasonably intelligent, the long term impact on my employability and earning power has been considerable. Relative to this, the sum I received from EIG was by any standard of pastoral care, derisory and heartless, especially when delivered through the bewildering legal games that EIG plays out.'

He warns the settlements are offered 'under duress' because survivors know they cannot afford to challenge the amount in courts.

At the time EIG said they had no basis to revisit Gilo's settlement and insisted they had dealt with his case with 'with patience and sensitivity'. 

In a statement, the EIG said: 'As independent insurers, we are not responsible for the abuse perpetrated by those for whom the church is accountable. Our role is to handle insured claims for financial compensation fairly for these acts of abuse.

'We and other insurers are bound by comprehensive, industry-wide regulation that oversees the way we operate and handle claims, and by the civil justice system.

"It is not in our gift to change civil law, which defines the claims process. Negotiations between lawyers – characterised in the bishops' letter as 'horse trading' – are a normal part of that process. So are full and final settlements, which bring certainty to all parties within the civil justice system.

'It is, however, in the Church of England's gift to provide further compensation as well as ongoing pastoral care to victims and survivors of clergy abuse if it so wishes.'

The Bishop at Lambeth, Tim Thornton, who was one of the bishops Gilo said he told of his abuse, spoke to Gilo earlier today to acknowledge receipt of the letter and said the Archbishop of Canterbury was in Kenya but would respond when he returned.

A Lambeth Palace spokesperson said: 'We take extremely seriously all communication from survivors and will be considering the contents of this letter very carefully in the weeks to come.'