Description A man has been jailed for 21 years after being convicted of historical sex attacks on children.Martin Clifford, 45, targeted four separate victims between 1988 and 1997 in Slough, Berkshire, and Horley in Surrey.Police said his victims had endured "sustained traumatic experiences".Clifford of Chatfield, Slough, was convicted of two counts of rape of a child under 16 and five counts of indecent assault on a male under 16.He was also found guilty at Reading Crown Court of two counts of indecent assault on a girl under 16, and five counts of indecency with a child under 14.Det Sgt Emma Skinner said: "The victims in this case had to endure sustained traumatic experiences at the hands of Clifford during their childhoods, which has had a profound impact on them throughout their lives."The strength they have displayed during the investigation and the trial has been incredible and I commend them all."