[3] He was called to the Bar by Gray's Inn in 1969,[4][5] and was a leading criminal barrister, acting as a prosecutor and a defender.

[9] In December 2016, the British Horseracing Authority (BHA) announced that, following an open competition, it had appointed Barker as its first judicial panel chairman.

[11] Barker is married to Dame Anne Rafferty one of the United Kingdom's few female Appeal Court judges,[12] with whom he has three daughters.

[13] Barker is a Governor of Sir John Cass's Foundation, one of London's oldest and largest education charities, which was founded in 1748.

Barker was appointed Commander of the Order of the British Empire (CBE) in the 2015 New Year Honours for services to the administration of justice and to charity.