Merseyside s Chief Constable Andy Cooke QPM, pictured with crime commissioner Jane Kennedy, to retire after 36 years police service. MERSEYSIDE S Chief Constable has announced his retirement after 36 years police service. After joining the force in 1985, Andy Cooke served as detective at every rank, including having responsibility for the robbery squad and targeted operations at the Major Crime Unit. In 2004, he established and became first commander of the nationally-recognised ‘Matrix’ team, responsible for tackling gun and gang crime. Two years later, he became area commander for South Liverpool, during which time he devised a nationally applauded approach to tackling serious organised crime within the security industry.