The British government secretly believed Israeli bungling was to blame for the massacre of Palestinian refugees during the 1982 Lebanon War.

Hundreds were murdered by Lebanese Christian militiamen at the Sabra and Shatila camps in Beirut. Israel was internationally condemned for allowing the troops into the camps.

But documents, newly released by the national archives under the 30 year rule, show that the then-UK Foreign Secretary Francis Pym told Prime Minister Margaret Thatcher that Israel did not intend the killings to happen.

In a private telegram, he said the massacre was ‘‘so obviously against the interest of the [Israeli] government’’ that it would not have intentionally enabled the Lebanese “in the slaughter of civilians”.

Instead, he blamed Israeli ‘‘incompetence’’ and ‘‘miscalculation’’.

A private note showing Mrs Thatcher’s view of the Palestine Liberation Organisation has also been released. She wrote: ‘‘I do not meet the IRA… and I will not receive the PLO. Tell our Arab friends if there are terrorist organisations in their countries, I will not receive them.”