If biographers leave their imprint on their subjects, the converse is equally true. Shortly after telling a seminar about Gladstone's formidable, long-lived energy the 74-year-old Lord Jenkins was seen, accompanied by three younger historians, on the kerb of Russell Square as the pedestrian lights went red. While they waited, thinking not to rush the old boy, the Chancellor of Oxford University charged for the other side ahead of onrushing traffic.