Karla is a 14-year old girl with Asperger's Syndrome (a form of autism) and cuts a pathetic figure. Bullied from the moment she set foot in school, she's a child badly let down by the system which failed to diagnose her condition, writing her off as a truculent troublemaker. Before her arrival at Waterloo Road she was excluded from three schools and the Bentham family eventually cracked under the pressure, with the father walking out on his wife and daughter, unable - or unwilling - to cope any longer. Karla was removed from her last school when mother Annette was given the choice - find another school or face permanent exclusion. She just prays that Waterloo Road will be the place for Karla to realise her potential.

Karla finds it difficult to make friends and she is a natural victim; her literal interpretation of simple instructions has always been the fuel for spiteful pranks and easy laughs. Karla exhibits a few psychological conditions most notably Obsessive Compulsive Disorder and depression - they have worsened since her parents' recent separation. She doesn't understand affection and can't deal with physical contact - something which breaks her mum's heart when Karla shrinks away from her embraces.

Karla is very intelligent and with the right understanding and guidance could do well at school.