His name is Sid - Soil Improvement Device - and it is the brainchild of 'Rammed Earth' specialist Michael Thompson.
It cost just £45.00 (including the the drill which costs £20.00) to make and will process one tonne of soil every hour, separating the soil from the stones; not only that, stones are graded into two sizes of 12mm and 25mm.
I can see SID being a great investment for gardeners. Not only to sieve soil but to grade composts too.