William Arthur Adcocks (born 11 November 1941, in Coventry) is a British former long-distance runner who competed in the 1968 Summer Olympics.

[2] In 1965, he won the Amateur Athletic Association of England title in the marathon, held in Port Talbot, beating nearest rival Brian Kilby by over 40 seconds.

[7] In 1966, he represented England and won silver medal in the Commonwealth Games marathon, finishing 5 seconds behind Scotland's Jim Alder.

[7] Later that year he ran his personal best for the marathon distance while winning at the Fukuoka Marathon, running 2:10:48, a time which was just a minute outside the world record (which had been set on the same course a year previously) at the time, and was a new European record.

[14][17][18] He also raced in the CAU (Counties Athletics Union) 20 Miles Championships, winning the title.