A civil trial in the Channel island of Jersey could become the longest and costliest in the UK dependency's judicial history. 

The action is being brought by members of the Saudi Arabian Alhamrani family, who run a group of industrial companies in Saudi Arabia, against JP Morgan ( Jersey) Trust. It centres around two trusts set up in Jersey in 1998 to hold most of the Alhamrani family's foreign investments.

Sheikh Mohamed Ali M Alhamrani heads the plaintiffs and is bringing the action with four of his brothers, alleging breach of trust, conflict of interest, gross negligence, and lack of communication between trustee and beneficiaries.

There are also similar complaints against Sheikh Mohamed's younger brother, Sheikh Abdullah Ali M Alhamrani, who is protector of the trusts. JP Morgan ( Jersey) Trust and Sheikh Abdullah deny these complaints.

In addition there are claims by the plaintiffs against a local trust company called Russa Management, which are also denied. To date, the claims with interest exceed $120 million.