This was a very unusual find in a field that we use for making and composting woodchips. Never seen before on the farm, it's a 'red cage' fungus, Clathrus ruber.
The fruiting body is a really strange looking thing that has a lattice structure like a cage or basket, but is red and appears slightly slimy.
Apparently it's not edible, but also quite rare. Whatever, it was a pleasure to look at and I hope it returns (or rather appears) again next year.