Michael Denzil Xavier Portillo FRSGS (/pɔːrˈtɪloʊ/ por-TIL-oh; born 26 May 1953) is a British journalist, broadcaster, and former Conservative Party politician. His broadcast series include railway documentaries such as Great British Railway Journeys and Great Continental Railway Journeys. A former member of the Conservative Party, he was Member of Parliament (MP) for Enfield Southgate from 1984 to 1997 and Kensington and Chelsea from 1999 to 2005, holding a number of ministerial and Cabinet positions.

Portillo obtained a first-class degree in history from the University of Cambridge, having been a student at Peterhouse. He began his working life as a graduate trainee with the transport company Ocean Group plc, before joining the Conservative Research Department (CRD) in 1976. First elected to the House of Commons in a 1984 by-election, Portillo served as a junior minister under both Margaret Thatcher and John Major, before entering the Cabinet in 1992 as Chief Secretary to the Treasury. He was promoted to Secretary of State for Employment in 1994. A Thatcherite and a Eurosceptic, he was seen as a likely challenger to Major during the 1995 Conservative leadership election, but did not stand, and was subsequently promoted to Secretary of State for Defence. As Defence Secretary, he pressed for a course of "clear blue water": purist policies separating the Conservatives from the Labour Party.

Portillo unexpectedly lost the theretofore safe Conservative Enfield Southgate seat at the 1997 general election. This led to the coining of the expression "Portillo moment". Returning to the Commons in the 1999 by-election in Kensington and Chelsea, Portillo rejoined the frontbench as Shadow Chancellor of the Exchequer. Standing for the leadership of the party in 2001, he came in third place behind Iain Duncan Smith and Kenneth Clarke. He retired from the House of Commons and from active politics at the 2005 general election.

Since leaving politics, Portillo has pursued his media interests by presenting and participating in a wide range of television and radio programmes. Portillo's passion for steam trains led him to make the BBC documentary series Great British Railway Journeys, beginning in 2010, in which he travels the British railway networks, referring to various editions of Bradshaw's Guide. The success of the show led Portillo to present series about railway systems in other countries. In 2022 he began to present a political show Portillo for the British news channel GB News.

Portillo was born in Bushey, Hertfordshire, on 26 May 1953 to an exiled Spanish republican father, Luis Gabriel Portillo (1907–1993) and a Scottish mother, Cora Waldegrave de Portillo (née Blyth; 1919–2014). Portillo's father, a devout Catholic, was a member of left-wing movements in the 1930s and fled Madrid when it fell to General Franco in 1939, settling in England. He became head of the London Diplomatic Office of the Government in Exile in 1972. Portillo's maternal grandfather, John Waldegrave Blyth (1873–1962), was a prosperous linen manufacturer from Kirkcaldy, who left an art collection worth millions to the Kirkcaldy Galleries.

Portillo was registered as a Spanish citizen at the age of four, and in accordance with Spanish naming customs (which require a person to have two surnames) his Spanish passport names him as Miguel Portillo Blyth. Portillo's now well-known "love affair with trains" started when he was a youth. He owned a clockwork train set, and envied friends who had electric ones. Additionally, his mother took him on 13-hour trips from London to Kirkcaldy aboard a steam-hauled night train, the Starlight Special, to visit his British grandparents, and he had summer holidays on the Isle of Wight, where he "loved" the steam railway between Ryde and Ventnor.

In 1961, aged 8, Portillo appeared in a television advertisement for Ribena, a blackcurrant cordial drink. He was educated at Stanburn Primary School in Stanmore, Greater London, and Harrow County School for Boys and was awarded a scholarship to Peterhouse, Cambridge, where he studied history. While at school Portillo had supported the cause of the Labour Party; he attributed his embrace of conservatism at Cambridge to the influence of the right-wing Peterhouse historian Maurice Cowling.

In 1982, Portillo married Carolyn Claire Eadie.