soil pests

In my allotment there is one patch of soil approx 20ft x 15ft that is infested by  small worm like things that are about 1/4 to 3/8 inch long silvery grey in colour and about a milimetre wide, when resting they coil up like a spring. All winter I put potatos on sticks and buried them and after a week lifted to find them infested with with these creatures,

At the moment I have lost nearly all of the greens that were planted out due to a mixture of cabbage root fly lavae and the silver worms. Has anybody any idea what they are and how to rid the plot of them?

Sounds like it may be wireworm .. they love to burrow into potatoes..They are hard to get rid of and you are doing the best thing already....keep going with the potaotes on sticks and destroy everything that comes up... there are some nasty chemicals on the market that claim to help but you will eventually get to the end of them doing just what you are doing

Thanks for that susan I really dont want to use any chemicals so potatos it is