Three senior bishops have made public a letter they wrote to the prime minister about hopes for peace in the Middle East after he failed to reply.
Bishop Michael Langrish was one of the signatories on the letter
The letter, written three months ago, accused Israel of undermining the chance of a future Palestinian state.
The Bishops of Exeter, Winchester and Coventry believe only a two-state solution will create peace.
But they said that this would soon become impossible unless international pressure was placed on Israel.
The Bishop of Exeter, Michael Langrish, the Bishop of Winchester, Michael Scott-Joynt, and the Bishop of Coventry, Colin Bennetts, sent the letter privately to Gordon Brown on June 13, and decided to make it public after failing to get a response.
The bishops singled out what they called the "segregation wall", telling Mr Brown he would be horrified to see how it cut Palestinians off from farmland and water supplies.
The Israeli government says the West Bank barrier is a security measure to stop suicide bombers.
Critics say the structure is part of an effort to annex occupied land and it has been declared illegal by the international Court of Justice.
They argued that the barrier should not be allowed to become Israel's new border because it would constitute the expansion of Israeli territory by force.
Bishop Langrish told the BBC News website that they were not intending to embarrass the prime minister by releasing the letter.
He said they thought it was important to get a response before the forthcoming peace conference.
"We all have a long-standing engagement with the Middle East and we are often asked about our government's real position on the issue given he had made some interesting speeches," he said.
"We were asking him to clarify the approach of the government in this area."
The bishops claimed that the alternatives to a two-state solution were a mass movement of population or some form of apartheid, both unacceptable.
Meanwhile, they said, the possibility of any independent Palestinian state being viable would shortly disappear.
A spokesman for the Prime Minister said Downing Street's correspondence unit has no record of receiving a letter dated June 13, but had received a follow up on September 25.
He said: "They thought a reply to this had gone out yesterday, possibly today. It should be with the bishops shortly."