In the memo, whose subject line is ‘Flying Saucers’, Agent Hottel reveals that an Air Force investigator had stated that ‘three so-called flying saucers had been recovered in New Mexico’.

The investigator gave the information to a special agent, he said. The FBI has censored both the agent and the investigator’s identity.

Agent Hottel went on to write: ‘They were described as being circular in shape with raised centers, approximately 50 feet in diameter.