An engineer believes he has cracked the secret to winning Poohsticks and has created a formula to finding the "perfect stick".
The game, which first appeared in A. A. Milne’s classic children’s story The House at Pooh Corner in 1928, involves players throwing sticks over the upstream side of a bridge into a river.
The winner is the person whose stick emerges from under the bridge first.
Dr Rhys Morgan, director of engineering and education at Royal Academy of Engineering, said the ideal stick should be thick, dense and as rough as possible.
Morgan's research is part of a new book - The Poohsticks Handbook: A Poohstickopedia - which reveals the secrets to finding the perfect poohstick, the best places in the country to play and poohsticks throughout history.
A survey of 2,000 parents commissioned to mark the release of The Poohsticks Handbook found that 57% of respondents regarded Poohsticks as a game of "chance", reported ITV News.
But according to Morgan, it's not chance at all.
He came up with a slightly confusing-looking formula: PP = A x I x Cd.
PP stands for 'perfect Poohstick', A is the cross-sectional area (thickness) of the stick which should be thicker to increase the drag, I is the stick's density which should be very dense and Cd is the drag coefficient (or shape) of the stick, which should be rough.
The properties of the perfect stick, Dr Morgan said, increase the water's influence on it, so it will be carried quickly.
The dense nature of the stick also means it will sink just below the surface where the fastest part of a stream lies.
How did Morgan come up with this formula? By playing a lot of Poohsticks.
The book also includes VisitEngland's 12 best 12 Poohstick bridges in the UK, in addition to the original Poohsticks Bridge in Ashdown Forest, East Sussex.
The top 12 Poohstick-perfect bridges, are:
Sheepwash Bridge, Ashford in the Water, Derbyshire
Morden Hall Park, London
Heale Gardens, Salisbury, Wiltshire
Packhorse Bridge, Watendlath, Cumbria
Mottisfont, Romsey, Hampshire
Little Wittenham Bridge, Abingdon, Oxfordshire
Mathematical Bridge, Cambridge, Cambridgeshire
New Lower Bridge, Boscastle, Cornwall
Bridge over Bourne Eau, Bourne, Lincolnshire
Cantlop Bridge, Shrewsbury, Shropshire
Essex Bridge, Shugborough, Staffordshire
Hutton-le-Hole, Ryedale, North Yorkshire