 Lombardo's signal was intercepted by British Intelligence.As a result, Prime Minister Margaret Thatcher and her War Cabinet, meeting at Chequers the following day, agreed to a request from Admiral Terence Lewin, the Chief of the Defence Staff, to alter the rules of engagement and allow an attack on "General Belgrano" outside the exclusion zone.Although the group was outside the British-declared total exclusion zone of 370 km (200 nautical miles) radius from the islands, the British decided that it was a threat.