Britain drew up secret plans to cut off the flow of the River Nile in 1956 to try to force Egypt's President Gamal Abdel Nasser to give up the Suez Canal, according to official files published for the first time Friday. Papers released under rules allowing sensitive documents to be made public after 50 years show military planners believed they could reduce the White Nile to a trickle, hitting agriculture and cutting communications. The plan was presented to Prime Minister Sir Anthony Eden just six weeks before British and French forces invaded Egypt in November 1956 in a catastrophic operation to seize the canal following its nationalization by Nasser. The Nile-blocking scheme was never adopted because of fears it could prompt a violent backlash. In the event, Eden and the French colluded with the Israelis who launched an attack on the canal zone to give the Anglo-French force a pretext to go in. But the day after the attack, a humiliated Eden was forced to declare a ceasefire in the face of concerted international pressure to withdraw led by US President Dwight Eisenhower. Under the Nile plan, Britain would have used the Owen Falls Dam in Uganda to cut the flow of the White Nile by seven eighths. However, the papers show, it would be 16 months before this would have an appreciable effect on river levels in Egypt, while there would be "serious repercussions" in other friendly states such as Kenya and Uganda. While Egypt's cotton and rice crops would be damaged, it was unlikely to destroy the economy or cause serious famine. "Since the river is vital to Egypt they have always been uneasy about British control of the headwater," the planning paper warned. "Thus any suggestion of controlling the Nile without Egypt's consent is certain to cause the most violent repercussions." Despite Eisenhower's opposition to the seizure of the canal, Britain's MI6 security service had been secretly working with the CIA on a plan to bring down Nasser, who Eden regarded as a Middle Eastern Hitler, the papers showed. On October 8, a month before the invasion, Cabinet Secretary Sir Norman Brook reported to Eden on secret talks the chairman of the Joint Intelligence Committee Patrick Dean had been holding in Washington with the CIA and the State Department. "The American agencies have joined with us in declaring that our joint objectives require Nasser's removal from power," Brook said. But as British and French warplanes took off for the attack, Dean reported that US Secretary of State John Foster Dulles wanted key passages removed from the joint Anglo-American paper on the talks directly stating that the objective was to get rid of Nasser. Other papers released Friday showed Eden was secretly urged to cover up the fact that his attorney general had warned that the invasion of Egypt over Suez was illegal. The papers showed that Brook was so concerned that he advised Eden to make no mention of the legality of the 1956 military action.