Reports from northwest London suggest a strange kind of vandalism is afoot. According to Harrow Council, £15,000 worth of drain covers have been pinched from Pinner and South Harrow over the past fortnight. Some kind of performance art, you might speculate? Could be, although the cast-iron gully grates (which often date back to the time the roads were built) are highly sought-after by unscrupulous metal merchants. With scrap iron fetching a pretty price of......