Whittle was born in 1964 growing up in the Scottish town of Troon. His father was a sprinter and ran until his late teens but other than that his family background was not overly sporty. As a boy, Brian tried a wide range of sports, enjoying many of them. He has maintained that his talent lay in his ability to train. He was educated at Marr College, Glasgow University and Kilmarnock College.
Senior career
At club level, Whittle ran for both Ayr Seaforth and Enfield & Haringey. His best performance in the 400 m was 45.22 at the 1988 Summer Olympics in Seoul. He finished 1st in his heat, 3rd in the quarter-final, but did not progress past the semi-final. He ran 45.5 on the first leg of the 4 × 400 m relay, but for once the GB team performed below par and finished fifth in the Olympic final. Perhaps his greatest achievement, and what he is best remembered for, is the manner in which he helped Great Britain win the Gold medal in the 4 x 400 metres relay at the 1986 European Championships in Stuttgart. He ran the third leg of the race with one shoe, running a personal best leg time of 45.09. As he took the baton from Kriss Akabusi, Akabusi stood on his shoe and it ripped off, leaving him to run the race without it. The other members of the team were Roger Black and Derek Redmond, all of whom ran Personal Best times on the day. Whittle also won a relay gold medal in the 1994 European Athletics Championships4 × 400 metres relay team alongside David McKenzie, Roger Black, and Du'aine Ladejo. He also ran in the heats of the 4 × 400 m relay at the 1990 European Championships in Split. He moved to 800 m after the 1988 Olympic Games, and ran in the final of the 1990 Commonwealth Games 800 m in New Zealand, where he finished fourth ahead of Sebastian Coe and Tom McKean. Whittle ran the last leg of the Commonwealth Games 4 × 400 m in 1990, anchoring the Scottish Team to a silver medal. He ran 44.7 seconds for his leg. He also ran the 800 m in the 1991 World Championships in Tokyo. His personal best for 800 m was 1:45.47 in 1990. Other notable performances included running 45.98 at the 1988 European Indoor Championships in Budapest winning the silver medal – a feat he repeated in 1989. He ran the last leg of the winning 4 × 400 m relay in the Europa Cup in 1989, helping Great Britain to win the team title for the first time. Whittle was an international schools' high jumper, and also competed in the 200m at the 1986 Commonwealth Games, making the semi-final.
Whittle sparked a row over the two-child cap on tax credits by claiming “there is no such thing as a rape clause”, claiming it was impossible to debate the controversial welfare reform as “the term rape clause is an invention to beat the Tories with”. The remarks were widely condemned and described as “skin-crawling” by other parties.