Keep clear

If you’re an habitué of the North Sea you’ll be aware of the fact that the small rings charted around gas and oil platforms mean you must keep at least 500 metres clear. If you’re just passing through, you might have missed the note on the chart, so look out for the pecked circle. At night, most of these platforms and associated structures flash out Morse code ‘Uniform’. In old money, this means ‘You are standing into danger’!