In 1928, a young Scotsman called Alec, returned from his holiday at the Dhoon, to his laboratory in Praed Street, Paddington, London. He had gone away in a rush and left piles of Petri dishes in his sink, which looked even murkier and dirtier on his return. He began to stack them in Lysol and found that one of them was different from the rest. It made him stop and say, "That's funny." Some mould was growing on one of the dishes - not too unusual - but all around the mould, the staphylococcus bacteria had been killed - very unusual. He took a sample of the mould, and found it was from the penicillium family.

The rest, as they say, is the history of Alexander Fleming. He has even had a pub in Praed Street named after him, generally referred to by the medical students of St Mary's as The Phlegm. Whenever I think of this wonderful breakthrough , and the thousands of lives that certainly have been saved as a result of this accidental discovery, most confusingly, the colour orange of poisonous toadstools comes into my mind. I cannot explain it, but I recognise its power.

The most dramatic colour encompassed by serendipity is red. How else could anyone regard that chance meeting - that irresistible tug of physical chemistry between two people, who glance across a crowded room - that is love at first sight? An all-embracing blush of racing thoughts, of strenuous efforts to remain outwardly calm, of trying to gauge whether the attraction is mutual, all add up to the lucky chance meeting being a strong burst of red. Of course, if this chance meeting becomes a lasting partnership, the red mutates into a collection of soft rainbow colours, ever changing, but bonded perfectly.

The greatest gift serendipity can bestow on us is the suggestion, as in the words of "Monty Python's Life of Brian", we always look on the bright side of life. It is amazing how many serendipitous moments there are if we are receptive to lady luck.