Sherlock holmes is not just doing wonders for bbc 's ratings , the eccentric sleuth can perhaps also be credited with re-igniting the fortunes of british heritage label belstaff whose tweed overcoat has become a latter-day cape and deerstalker .
You might think that clay johnson , a campaigner for transparency , would be pleased to see a ferret , with a deerstalker hat and magnifying glass , pop up on his screen .
