Paracetamol (aka acetaminophen or Tylenol) by itself is not an addictive medication. However, when combined with other medications like codeine (Tylenol #3) or hydrocodone (Vicodin, Lortab), the medication can become addictive. It is the medication it is combined with, NOT the paracetamol that is giving it the potential for abuse.

In the US medications with abuse potential are called controlled substances. The FDA assigns a number (levels 1-5) to these medications based on how high the potential for abuse is. Level 1 would have the highest potential for abuse and level 5 the lowest. I can't tell you how this works in the UK though.