We found these cooked "wild crayfish tails" at the neighborhood grocery for £2.99 for 180 grams, or about $6 for just under half a pound. That's about what I pay for crawfish in San Diego but more than double what they go for in Louisiana.
According to the packaging, the tails came from Warminster Wilts, a town west of London near the city of Bath. An American variety of crawfish apparently was introduced into local lakes in the 1980s and prospered to the point of becoming a threat to the smaller indigenous variety of the critters by 2001.
I combined the tails with sauteed onions, eggs and cheese to produce a tasty frittata.
With the dollar worth so little and exchange rates being so poor, you basically double the price of anything here to estimate the cost in dollars. We're avoiding restaurants as much as possible while we're here to keep from blowing through our retirement savings on this trip.