Ken Wharfe, the Princess's former Metropolitan Police bodyguard, told The Daily Telegraph: "If these parents were so concerned that this information was relevant or had some general import, then they should have delivered it to the inquest.
"Why has it taken so long to air this new information? It seems so shallow to me. I just think it's a bit of a publicity stunt.
"For what reason I'm not certain, but in the absence of any real evidence, I'm sure this will go away."
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Police said the arrest showed how the matter was being taken "extremely seriously".
Windy with a soaking and limited winter sunshine
Mr Johnson said the checks would not be on goods travelling into Britain from the six counties.