def get_gb_person_id(acc_id, vehicle_index, person_index):
    """
    Returns global person id for GB, year and index of accident.

    The id is constructed as <Acc_id><Person_index>
    where Vehicle_index is two digits max.
    """

    person_id = acc_id * 1000
    person_id += vehicle_index * 100
    person_id += person_index

    return person_id