1. A computer-implemented method of analyzing messages in a computer system to allow workflows constituted by the messages to be identified, the method comprising: analyzing a sequence of messages in a computer system to classify each of the messages and produce a corresponding sequence of classifications of the messages; applying sequence induction to the sequence of classifications of the messages and determining a temporal proximity of classifications in the sequence of classifications to produce a set of sub-sequences of the classifications of the messages and a sequence grammar for the sub-sequences, from which a workflow constituted by the sequence of messages is identified in order to create a control policy stored in the computer system; receiving a new sequence of messages; comparing the new sequence of messages with the workflow in the control policy; and in response to the new sequence of messages being acceptable by the control policy, sending an output message sequence to a destination computer resource, and wherein in response to the new sequence of messages requiring further action in accordance with the control policy, sending an alternative output message sequence to the destination computer resource.