Sports commentator Gary Lineker described the thief who stole his mother's car a 'rotter'. Rotter is a very restrained insult, but then Gary Lineker is known for his goody-goody image. Rotter is also rather old-fashioned these days, and a piece on the BBC website looks at other dated insults, including bounder and cad.
Rotter, as the OED makes clear, is usually used about men these days, although that wasn't always the case, as citations in the Dictionary prove (eg one from Gilbert Swift from 1900 reads "He liked his mother and sisters..: all other women he classed as ‘rotters’"). Rotter, and the similar words cad and bounder, hark back to the class system - they are people who are vulgar and morally corrupt. As the author of the BBC piece says, "if you really want to hurt someone in Britain, you bring up their social status" - the fact that the 'pleb' affair is still in the news over a year after the actual incident is proof of that.
Insults have moved on from cad, bounder and rotter, but probably nothing today can match the richness of Shakespearean insults, such as this line from Henry IV, Part I: "This leathern jerkin, crystal-button, not-pated, agate-ring, puke-stocking, caddis-garter, smooth-tongue, Spanish pouch".
For the story, see this BBC page.