The father of captured Israeli soldier Gilad Shalit has said that even though Ehud Olmert is stepping down as Israel's prime minister, he must get his son back.
Noam Shalit has had no word of his son's condition since June
Noam Shalit, in London to raise the international profile of his son's captivity, told the BBC: "I am frustrated from the idea that in 27 months the government didn't manage to fulfil its duty for a combat soldier that was captured."
In an interview with the TV programme HARDtalk with Stephen Sackur he said: "I am still demanding Ehud Olmert to resolve this issue before he steps down from his office.
"Because this crisis happened on his shift and he has to conclude it before he finishes his shift. I am definitely sure it's his duty and responsibility to bring back Gilad."
Corporal Shalit, who is now 22, was seized in a cross-border raid by Palestinian militants on an army post near the Gaza Strip in June 2006. Two other Israeli soldiers were killed in the raid.
He was on his first mission with a combat unit of the Israeli army, having left high school only 11 months previously.
"I think that Israel should pay a high price for Gilad because Gilad was on a military mission, he was a solider."
Mr Shalit corrected himself: "He is a soldier. It's not his choice. Military service is not his occupation or his career."
The Shalit family have heard nothing from Gilad since June, when his captors passed them a letter through intermediaries.
Gilad Shalit, 22, has been held in the Gaza strip for 27 months
While in London Mr Shalit met Amnesty International to urge them to do more to help them.
He told Stephen Sackur: "We know nothing about his situation because his captors deny any access to him, any contact with him. It is a continuous nightmare for us.
"It's day by day a struggle to urge people, decision makers, to resolve this crisis. There is no progress at all."
Hamas has asked for 450 named prisoners to be exchanged for his son.
Mr Shalit said: "I think Israel accepted this principle of releasing Palestinian prisoners, some of them with blood on their hands."
But, he said, the government had not done enough to pursue the possibility of a prisoner swap and now it seemed the Hamas agenda had changed.
There had been no meaningful negotiations since April 2007, he added: "The prisoner issue is a low priority issue now."
Mr Shalit says the Israeli government should not lift the economic blockade on Gaza until his son is freed.
Israel imposed an economic blockade on Gaza after Hamas forces violently seized control from Fatah in June 2007.
Only basic humanitarian items have been allowed into Gaza since 2007
With no raw materials getting in and no finished products getting out, the economy has collapsed and thousands are unemployed.
One million people, 70% of the population, live on UN food aid.
"A million and a half non-involved Palestinians are suffering from the day that Gilad was kidnapped from boycott, from air raids and especially from the boycott, from the shortages of food and goods.
"They have to go to their Hamas leaders and say, 'Release Gilad Shalit because we suffer from this Gilad Shalit.' I think Israel has to use all its leverage on Hamas."
Mr Shalit said that his family had not despaired of seeing Gilad's release but he said: "I believe Gilad has become a pawn in this overall Middle East conflict.
"He has become a political chattel. Whenever Gilad Shalit's name is raised suddenly all the Middle East's problems are raised as well.
"The bottom line is that in 27 months the Gilad situation hasn't changed a bit.
"We can say that he went backwards because the longer he's in captivity I don't know how does it affect on his health, his mental health, his physical health."
The HARDtalk interview with Noam Shalit will be broadcast on BBC World News on Tuesday 23 September at 0330, 0830, 1430, 2030, and 2230, and on BBC News channel on Tuesday 23 September at 0430 and 2330.