In fact, all three of the meanings cited by erias, evilrooster and rawprawn (pregnant, awakened and cobbled together) have been commonplace in British English since the 18th or 19th century; the meaning is unlikely to be ambiguous because of contextual clues, so all have survived, although the "awakened" meaning is becoming less and less useful as watches/phones/radios etc. with alarms on become ubiquitous.
It is nonetheless probably worth noting that in days gone by, when the UK still had heavy industry and an alarm clock was a luxury item, that some factories actually employed a "knocker-up" whose job was to bang on workers' doors half an hour before their shifts began.