

Introduction
Derek Hallas was an English rugby union and professional rugby league footballer of the 1950s and '60s, playing representative level rugby union (RU) for Yorkshire, and at club level for Roundhay RFC, as a Centre, i.e. number 12 or 13, and playing representative level rugby league (RL) for Great Britain, and Yorkshire, and at club level for Keighley (twice), Leeds, and Parramatta Eels, as a Centre, i.e. number 3 or 4.
Playing career
International honours
Derek Hallas won caps for Great Britain (RL) while at Leeds in 1961 against France, and New Zealand.
County honours
Derek Hallas represented Yorkshire (RU) while at Roundhay, and represented Yorkshire (RL) while at Keighley.
Championship Final Appearances
Derek Hallas played Centre, and scored two tries, in Leeds' 25-10 victory over Warrington in the Championship final during the 1960–61 season at Odsal Stadium, Bradford on Saturday 20 May 1961.
Club career
Derek Hallas played rugby union for Roundhay RFC, switching code to rugby league, he signed for Keighley in December 1953, signing for Leeds in January 1959 for £4,000 (based on increases in average earnings, this would be approximately £169,000 in 2009), he resigned for Keighley in October 1962 for £3,000 (based on increases in average earnings, this would be approximately £108,000 in 2009), before signing for Paramatta in April 1963.
Outside of rugby
As a child, Derek Hallas attended Hunslet Carr County Primary School.