An eel buck or eel basket is a type of fish trap that was prevalent in the River Thames in England up to the 20th century. It was used particularly to catch eels, which were a staple part of the London diet. Eel bucks were baskets made of willow wood, and were often strung together in a fishing weir. Construction of such weirs was outlawed under the terms of Magna Carta in 1215: This was intended to keep the rivers navigable by boat, however the practice continued unabated. Several islands in the River Thames reflect the presence of bucks at those points; for example, Buck Ait and Handbuck Eyot. A surviving eel buck may be seen on the River Test at 51.13°N, -1.48472°W.