Datu Omar Ali Datu Bachtiyal, 64, said he believed the suit was invalid “because we know that (the facts about the heirs) are mixed up, and, if we really study, (their status) is doubtful so this (status) is not true for me”.

He also disputed the lineage of one of the claimants, Taj Mahal Kiram-Tarsum Nuqui, who had claimed to be a grandson of Dayang Dayang Piandao, a princess and one of the administrators of the Sulu sultanate in 1936.

“It is a lie,” Omar Ali told Bernama recently. “Dayang Dayang Piandao never had a child, so how can she have a grandchild? Taj Mahal is the grandson of Tarahata and not of Dayang Dayang Piandao.”

Omar Ali said Dayang Dayang Piandao married Datu Ombra Amilbangsa and ascended the throne as sultanah in 1937 until her death in 1945.

He said his father and Datu Ombra Amilbangsa, who became the Sulu sultan in 1937, were first cousins.

A group claiming to be heirs of the last Sultan of Sulu was named in a series of suits against the Malaysian government and are seeking compensation for the cession of Sabah. In February 2022, a French arbitration court held that the government was liable to pay US$15 billion (RM63 billion) to them.

The government has contested the suit in France and in Spain. Last week, a Spanish constitutional court annulled the appointment of the arbitrator who had given judgment against Malaysia.

Omar Ali said the dispute could be properly negotiated and the arbitration process carried out peacefully without any contention.

He said he was never consulted by the group of individuals involved before they took the arbitration process to the Spanish constitutional court.