McWhirter is the youngest son of William McWhirter, editor of the Sunday Pictorial, and Margaret “Bunty” Williamson. He is born at Winchmore Hill, Middlesex, England on August 12, 1925. Like his two brothers, he is educated at Marlborough College and Trinity College, Oxford. Between 1943 and 1946 he serves as a sub-lieutenant with the Royal Naval Volunteer Reserve on board a minesweeper in the Mediterranean Sea.
Ross and his twin brother Norris become sports journalists in 1950. In 1951, they found an agency to provide facts and figures to Fleet Street, setting out, in Norris McWhirter’s words “to supply facts and figures to newspapers, yearbooks, encyclopaedias and advertisers.” In the same year they publish Get to Your Marks.
While building up their accounts, they both work as sports journalists. One of the athletes they know and cover is runner Christopher Chataway, an employee at Guinness who recommends them to Hugh Beaver. After an interview in 1954 in which the Guinness directors enjoy testing the twins’ knowledge of records and unusual facts, the brothers agree to start work on the book that becomes The Guinness Book of Records. In August 1955, the first 198-page green volume is at the bookstalls, and in four more months it is the UK’s number one non-fiction best-seller. Both brothers are regulars on the BBC show Record Breakers. They are noted for their encyclopedic memories, enabling them to provide detailed answers to questions from the audience about entries in The Guinness Book of Records. Norris continues on the programme after Ross’s death.
In the early 1960s, McWhirter is a Conservative Party activist and seeks, unsuccessfully, the seat of Edmonton in the 1964 general election. Following his killing, his brother and others found the National Association for Freedom (later The Freedom Association).
McWhirter advocates various restrictions on the freedom of the Irish community in Britain, such as making it compulsory for all of them to register with the local police and to provide signed photographs of themselves when renting flats or booking into hotels and hostels. In addition, he offers a £50,000 reward for information leading to a conviction for several recent high-profile bombings in England that were publicly claimed by the Provisional Irish Republican Army (IRA). In doing so, he recognises that he might then be a target himself. This is considered a “bounty” by the IRA Army Council, a view that leads directly to the events that follow, although the idea is not originally his, but that of John Gouriet.
At 6:45 PM on November 27, 1975, McWhirter is shot and killed by two IRA volunteers, Harry Duggan and Hugh Doherty, both of whom are members of what becomes known as the Balcombe Street Gang, the group for whose capture McWhirter had offered the reward. He is shot with a .357 Magnum revolver at close range in the head and chest outside his home in Village Road, Bush Hill Park. He is taken to Chase Farm Hospital but dies soon after being admitted. His killers are captured and charged with his and nine other murders. They are sentenced to life imprisonment but freed in 1999 under the terms of the Good Friday Agreement.