The court heard how the defendant swore and said “it’s really happening” when an undercover police officer sent him an image of a flight booking in preparation for the plot.
Ms Morgan added: “These, members of the jury, were the defendant’s words when he realised that another person, who he believed to be called David Nelson, was genuinely prepared to join him in his plan to attack Holly Willoughby.
“When he believed that David Nelson had just booked a flight to travel from the US … to join in that attack – ‘it’s really happening’.
“He didn’t say: ‘Don’t do that, I was just kidding.’ He didn’t say: ‘This is just fantasy, you haven’t bought a flight have you?’ He didn’t say: ‘I don’t really trust you because the name on your flight booking doesn’t match with your username’.”
Plumb’s previous convictions showed he had a “tendency” to commit acts aimed at controlling and terrifying women, Ms Morgan told jurors.
A ‘sly individual’
The prosecutor said the defendant knew why police had turned up at his flat to arrest him – describing him as a “sly individual”.
Ms Morgan said: “I suggest to you that he is a prolific liar who has sought to minimise the extent of his criminality.
“What you see is a sly individual – he knows why police are there … he knows what he’s got hidden away and he knows what’s on his phone.”
Concluding her closing speech, Ms Morgan told the jury: “There is a nasty reality to this man – Big Bear, I don’t think so. Big Bear, hardly.
“He shocked even those who were prepared to fantasise with him.
“This defendant was intent on making this happen.
“He knew that it would be a far more likely or effective plan if he could recruit others to that cause – the more numbers he had the more effective it was likely to be.”
Plumb denies soliciting murder, incitement to rape and incitement to kidnap.
The trial continues at Chelmsford Crown Court.