We want to say it loud and clear if you think clay soil is a problem:
Clay soil is fertile soil that conserves moisture!
Clay soil is good soil, native European plants love it and so do many other trees.
Relatively few plants like really waterlogged soil.
Clay soil becomes waterlogged more easily than other soils and can collect water in certain places, like basins or low lying ground, but really in most places it's fine to just plant into it.
When water sits in puddles for a long time after rain, one way to break surface water logging is to dig one or more soakaways or sumps.
These are a lot of work, so it's good that they do work.
Put them in first and use the soil that comes out to build ridges to plant into.
Clay is good for shaping into raised mounds.
In upland areas, clay soil's ability to preserve moisture is a good thing - it works well with mulch fabric.
Transplanted hedging and trees survive best in clay soils - it's plants on drier and sandier soils that need more watering in hot summer.
Long Term Years of Improving Clay Soil:
People who want to really improve the drainage in a plot of clay land each early winter will double dig it over with manure and lime, leaving big bare sods of clay on top, exposed to the frosts over the winter.
This can be covered in mid spring to dry off for digging with more manure and sowing with green manure fertiliser plants.