Palestinian leaders are threatening to sue the British government over a declaration it made in 1917 that led to the establishment of Israel.

"We hereby declare the establishment of a Jewish state in the land of Israel which will be called the State of Israel."

1948. Jews celebrated the state’s establishment. A catastrophe, according to Palestinians, who protest the outcome and implications of statehood to date.

The premise of that catastrophe, say Palestinian leaders, is grounds for a lawsuit.

"based on this ill-omened promise, hundreds of thousands of Jews were moved from Europe and elsewhere to Palestine at the expense of our Palestinian people whose parents and grandparents had lived for thousands of years on the soil of their homeland," said Palestinian Foreign Minister Riad Malki. 

The promise refers to the Balfour Declaration. A 1917 letter from then UK Foreign Secretary Lord Arthur Balfour pledging Britain’s support for the establishment of a home for Jewish people in Palestine.

Israel’s national archives are full of correspondences around that promise - including letters of protest from Palestinian leaders at the time.

A hundred years after the fact, the Palestinian authority says they’ll sue Britain’s government in an international court.

Palestinian Authority members declined to be interviewed for this story. But a prominent Palestinian Human Rights attorney told me that legally there probably are no grounds for this lawsuit. It’s about making a point.

Israeli leaders dismiss the threat.

"When it comes to the Palestinians I want to use a very specific word: Those are gimmicks. It has no content. It has no international meaning," said Israeli Deputy Foreign Minister Tzipi Hotovely.

Other critics - including former British foreign secretary Malcolm Rifkind, say a lawsuit is unlikely and would have no legal force.