The Cornish tourist board has urged people not to visit unless they have pre-booked and to test themselves extensively amid a spike in coronavirus cases in the county. Visit Cornwall chief executive Malcolm Bell said visitors should aim to “ treble their efforts as much as possible ” with the hands, face, space guidance and try to remain outdoors.It comes as the southwest county has seen a rise in cases in recent weeks after visitors flocked there for their summer holidays. Figures calculated by