Ammophila sabulosa is amongst my favourite wasps and now active on our sandy soils. The females prepare a burrow in anticipation of catching caterpillars for their young to develop on. The burrow is then concealed by blocking the entrance, in this case (at Cooper's Hill today) with a stone weighing more than the wasp! Once found, the caterpillar is dragged across the ground to the burrow, the wasp showing an amazing sense of direction and feat of memory.
This species is a mass provisioner - all the food is placed into the burrow in one go, then an egg laid. There is another species (not present in Beds to my knowledge), Ammophila pubescens, which is a progressive provisioner, keeping several burrows on the go, opening them up periodically to see which young need more food.