The Archbishop’s sermon echoed growing unease over the fate of Mr Johnston, who has now been held for longer than any other hostage in Gaza.

A series of protests by Palestinian journalists aimed at pressuring Palestinian leaders to secure his release have brought little progress so far.

Criminal families have become so powerful that local authorities can do little to control them. Ali Sartawi, Justice Minister of the Palestinian Unity Government, said: “It is impossible for us to implement the law because of the power and influence of the big clans. They are more powerful than us.”

It is still unclear who is holding Mr Johnston. The BBC says that it has not had direct contact with the kidnappers, though it has been told that he is well. Palestinian authorities say that they have yet to receive any demands. But some within the security services suspect that Mumtaz Dagmoush and his extended family are involved. The family was previously blamed for the capture of the Israeli soldier Gilad Schalit 10 months ago and of two Fox TV journalists last summer.

The clan was once loyal to Hamas, but switched allegiances last winter when two of their members were killed during factional fighting by Hamas gun-men. The incident sparked a series of retaliatory attacks. The violence often appears random.

The Dagmoush family live in a neighbourhood blocked off with burning tyres and concrete and patrolled by armed guards. It is a place where few from the Palestinian security services dare to tread.

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