Peacock earned himself a place in
John Kear's England side for the
2000 World Cup. He made four appearances in the World Cup that year, scoring an impressive six tries which including a hat trick against
Fiji at
Headingley. Peacock played for England in 2001 against Wales. Also in 2001, he capped the season by making his Great Britain début against
Australia scoring a try after just 86 seconds of his début in the first test victory at
Huddersfield. He then become a permanent presence in the Great Britain squad making 14 appearances, all but three of which have been in the starting line up. Peacock won
caps for Great Britain while at Bradford Bulls in 2001 against Australia (2 matches), and Australia (sub), in 2002 against Australia, New Zealand, and New Zealand (sub) (2 matches), in 2003 against Australia (3 matches), in 2004 against Australia (3 matches), and New Zealand, in 2005 against Australia (2 matches), and New Zealand (2 matches). Peacock was then selected in the
Great Britain team to compete in the end of season
2004 Rugby League Tri-Nations tournament. In the final against
Australia he played as a in the Lions' 44–4 loss. Peacock played for Great Britain while at Leeds in 2006 against New Zealand (3 matches), and Australia (2 matches), in 2007 against New Zealand (3 matches). He played for England in 2008 against France. On 16 June 2008, Peacock was announced as the
England captain for the
2008 Rugby League World Cup in Australia. In
Group A's first match against
Papua New Guinea he played as a in England's victory. He played against Papua New Guinea, Australia, and New Zealand (2 matches), in 2009 against France (2 matches), New Zealand and Australia. He was selected to play for England against France in the one-off test in 2010. On 26 June 2012, Peacock announced his retirement from international rugby league. ==Career stats==