garden won't dry out

our back garden is literally constantly soaking wet. weve checked neighbours drainage on a nearby outbuilding and the rain is going down a drain, yet our garden doesnt seem to be able to get rid of the water. We tried to turn over the top soil to plant some plants and literally as soon as you put the spade in the ground its like one big soaking wet mud fest........ we are at the top of the road so you would think it would be the houses down the road that were having problems, but next door up and down are both absolutely fine. I know the soil is quite clay based, but if anyone has any ideas on how to solve it. Terrified to plant out anything in it because the second it rains its just saturated on top of the grass.