Prime Minister Gordon Brown had a mishap with a kitchen sink earlier this week, which has highlighted an important lesson for people with contact lenses in the kitchen.Mr Brown dropped one of his contact lenses down the sink plughole in what Sky News has described as a kitchen sink drama.As a result, he was more than half an hour late to deliver a speech to the Scottish Labour Party Conference.Eventually, the lenses were recovered and the speech was given, but Sky News Jon Craig gave a tip to Mr Brown and other contacts wearers.If you ever need to make any adjustments to a contact lens while standing over a wash basin or sink, make sure the plug is firmly in the plughole in case the lens pops out of your eye, he stated.A spokesman for Mr Brown added that the prime minister was very grateful that the incident was resolved.While it may be viewed by many as common sense to keep lenses away from kitchen sinks, kitchen design guru Sharon L Sherman has insisted that common sense is the key element of a great kitchen.