This was quite bizarre given the number of things Constance has said that can't be true. The sub zero footmuff, the disappearing car seat, the remotely exploded car,.. we could be here all day.Think he was struggling to know what to say. It was also a bit weird when he started quoting from "Alice in wonderland", about believing in impossible things, and relating that back to CM buying petrol to have a DIY cremation. He was making the point ( I think) that the only logical reason for CM to buy petrol at that point was because her baby had just died. Therefore what the witnesses saw was impossible.
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Then by contrast Constance being in Seaford is supposedly "unpossible" but evidenced by an eyewitness and a receipt from the golf course.