St Laurences Church, Eastwood Standing Stone, Essex

Some things just make you ask questions. The geology of Essex, in the East of England, is virtually stone-free. So you have to ask yourself why this mediaeval church near Southend on Sea was bult over this particular stone. And why it wasn't incorporated into the foundations but left to stick up a few inches between the pews like this. Southend airport wants to extend the adjacent runway and demolish the Grade 1 listed church, so maybe a dig will show more. Will the stone be moved with the church, and is that such a good idea?