Butler started his career at Metropolitan Police before moving on to Concord Rangers in 2014.
Such was his form on the Island, that he was included in the England C squad two years ago.
The 24-year old then spent last season at Hemel, where he spectacularly scored from a drop-kick in the game at home to Sutton United in February!
Iron manager Jamie Day was pleased to secure the service of such a promising young keeper: "I've long been impressed with Jamie and he has done really well over the last couple of years. Stepping up to the National League level will be a great opportunity for him. He'll be an important part of the spine of our side".