Last week but one I was laid low for four days by a severe bout of food poisoning. After a rigorous process of elimination (Mrs Steve and I had eaten and drunk all the same things for days), it came down to the fact that I'd refilled my plastic water bottle at a very slow, suspiciously so, drinking fountain at the Vatican Museums. I'd offered to fill hers too (it was in tbe gents) but she declined. It saved me one euro. Looking back, it was not a sensible thing to do...