Rich wrote:
I'm looking to lay a path across my garden using a paving mould - the
sort where you pour in concrete then lift the mould off when partly
set. Should I put anything under the casting to act as a sort of
foundation or do you reckon the concrete would be Ok cast straight
onto mud?

As long as it's a couple of inches thick, it should manage light foot
traffic on mud. Much better to tamp a few inches of rubble underneath
though, it greatly increases the strength & durability.