Simpson was born in Cleveleys, Lancashire; his family later moved to Dunwich, Suffolk. His great grandfather was Samuel Franklin Cowdery (later known as Samuel Franklin Cody), an American showman in the style of Buffalo Bill Cody, who became a British citizen and was an early pioneer of manned flight in the UK. Simpson reveals in his autobiography that his father was an anarchist.

Simpson was educated at Dulwich College Preparatory School and St Paul's School, followed by Magdalene College, Cambridge, where he read English and was editor of Granta magazine. In 1965 he was a member of the Magdalene University Challenge team. A year later Simpson started as a trainee sub-editor at BBC radio news.

Simpson became a BBC reporter in 1970. He describes in his autobiography how on his very first day the then prime minister Harold Wilson, angered by the sudden and impudent, as he saw it, appearance of the novice's microphone, punched him in the stomach.

Simpson was the BBC's political editor from 1980 till 1981. He presented the Nine O'Clock News from 1981 till 1982 and became diplomatic editor in 1982. He had also served as a correspondent in South Africa, Brussels and Dublin. He became BBC world affairs editor in 1988. Simpson also presents the occasional current affairs programme Simpson's World.

Simpson's reporting career includes the following episodes:

• He travelled back from Paris to Tehran with the exiled Ayatollah Khomeini on 1 February 1979, a return that heralded the Iranian Revolution, as millions lined the streets of the capital.

• In November 1969 he interviewed the exiled King of Buganda, Mutesa II, hours before death in his London flat from alcohol poisoning. The official cause was suicide but some suspected assassination. Simpson told the police the following day that the king, a fellow-graduate of Magdalene College, Cambridge, had been sober and in good spirits, but this line of enquiry was not pursued.

• In 1989 he avoided bullets at the Beijing Tiananmen Square massacre.

• Simpson reported the fall of Ceau?escu regime in Bucharest later that year.

• He spent the early part of the 1991 Gulf War in Baghdad, before being expelled by the authorities.

• Simpson reported from Belgrade during the Kosovo War of 1999, where he was one of a handful of journalists to remain in the Serbian capital after the authorities, at the start of the conflict, expelled those from NATO countries.

• Two years later, he was one of the first reporters to enter Afghanistan in 2001, famously disguising himself by wearing a burqua, and subsequently Kabul in the US-led invasion of Afghanistan.

• Simpson was hunted by Robert Mugabe's forces in Zimbabwe.

• He was the first BBC journalist to answer questions in a war zone from internet users via BBC News Online.

• While reporting on a non-embedded basis from Northern Iraq in the 2003 Iraq war, Simpson was injured in a friendly fire incident when a U.S. warplane bombed the convoy of American and Kurdish forces he was with. The attack was caught on film: a member of Simpson's crew was killed and he himself was left deaf in one ear.

Simpson has freely admitted to experimenting with hallucinogenic drugs offered to him by locals in various jungles of the world. This prompted jibes from other panellists when Simpson appeared on BBC Television's topical quiz show Have I Got News For You. On his first appearance, Simpson revealed that one hallucination involved a six-foot goldfish putting his flipper round his shoulders while wearing dark glasses and a straw hat.

In 2008-9 Simpson took part in a BBC programme called Top Dogs: Adventures in War, Sea and Ice. It saw Simpson unite with fellow Britons Sir Ranulph Fiennes, the adventurer, and Sir Robin Knox-Johnston, the round-the-world yachtsman. The team went on three trips, each experiencing each others' adventure field. The first episode, aired on 27 March 2009, saw Simpson, Fiennes and Knox-Johnston go on a news-gathering trip to Afghanistan. The team reported from the legendary Khyber Pass and infamous Tora Bora mountain complex. The three also undertook a voyage around Cape Horn and an expedition hauling sledges across the deep-frozen Frobisher Bay in the far north of Canada.

Simpson has received various awards, including a CBE in the Gulf War honours list in 1991, an International Emmy for his report for the BBC Ten O'Clock News on the fall of Kabul, the Golden Nymph at the Cannes Film Festival, a Peabody award in the US, and three Baftas. He was appointed an honorary fellow of his old college at Cambridge, Magdalene, in 2000, and became the first Chancellor of Roehampton University in 2005. Various universities have awarded him honorary doctorates: De Montfort, Suffolk College at the University of East Anglia, Nottingham, Dundee, Southampton, St Andrews, and Leeds. He has received the Ischia Prize, Italy's main award for journalism, and the Bayeux Prize for war reporting.

Simpson has two daughters, Julia and Eleanor, by his first marriage to Diane Petteys, of El Cajon, California. He married Dee (Adele) Kruger, a South African television producer, in 1996. They had a son, Rafe, in January 2006. Simpson, whose grandmother was born in Ireland, holds British and Irish citizenship; he moved back to London in 2005 after living in Ireland for several years.

Simpson has written several books, including the following autobiographical volumes:

• Strange Places, Questionable People (1998)
• A Mad World, My Masters (2000)
• News From No Man's Land (2002)
• The Wars Against Saddam: Taking the Hard Road to Baghdad (2004)
• Days from a Different World: A Memoir of Childhood (2005)
• Not Quite World's End: A Traveler's Tales (2007)
• Twenty Tales From The War Zone (2007)
• Unreliable Sources (2010)