Really???

Foundations are supposed to be a metre deep of solid concrete.
In places, ours were only 12 centimetres deep ... Below that was a layer of loose, broken bricks.
Another load of concrete is due in the morning! At least then the underpinning will be complete. The patio will be restored to its former not-exactly-glory, and work on the new extension (above the existing ground floor extension that's being underpinned) begins in earnest on Monday.