The Fishmonger's Hall terrorist duped a security official about why he was wearing a bulky coat concealing a fake suicide vest shortly before the attack, an inquest has heard.
Usman Khan spoke with Steve Machin, governor of counter-terrorism at HMP Whitemoor, at a prisoner education event in central London where he would later stab and kill Cambridge graduates Jack Merritt, 25, and Saskia Jones, 23.
Mr Machin said he asked Khan why he was wearing the extra large coat, which he seldom removed, but said the 28-year-old jihadi’s answer about dressing for the weather was “plausible”.
And Mr Machin told the inquests into the deaths that he was not “in the same headspace” while outside the prison.
Mr Machin said: “I couldn’t live my life expecting every encounter with the community or ex-offenders is going to lead to devastation, I couldn’t live with that level of paranoia.”
On Wednesday, Mr Machin said Khan, from Stafford, tried to give him a hug when the pair met, telling him: “I have learnt that violence isn’t the path.”
But inquest jurors at City of London’s Guildhall heard Khan had spent the previous week buying items needed for his murderous plans, including a black coat that he wore to the event, under which he concealed a fake suicide vest.
On Thursday, Nick Armstrong, representing the family of Ms Jones who was a guest at the event, asked: “Why don’t you pick up the fact he’s wearing the coat?”
Mr Machin replied: “He provided a backstory and it sort of made sense. I could see below the coat was a base layer.
“He said when he checked the weather he was expecting a cold day. He said: ‘I don’t want this being my outer top’.”
Mr Armstrong accused Mr Machin of dropping his guard despite being faced with warning signs about Khan’s presentation.
Mr Machin said: “I’m not in the same headspace as when I’m at work – I wasn’t there as a counter-terrorism governor, I was there as operational manager of HMP Whitemoor.
“My head space would have been completely different.”
Mr Machin rejected Mr Armstrong’s suggestion that Khan being an example of a “good news story” for rehabilitation had effectively “blunted his antennae” of concern.
Mr Machin said: “I didn’t see it as a ‘good news story’.
“I saw him being involved (with Learning Together) as good, it hadn’t got to the point of a good news story.”
Mr Armstrong replied: “The problem with a good news story is they’re not always true.”
Georgina Butler, head of learning and skills at Whitemoor jail, was sitting with Mr Machin, Khan and Ms Jones at the Learning Together event at Fishmongers’ Hall.
She told jurors that she felt “flustered and warm” because she had got lost and was late to the event so took her jacket off and flapped her blouse to cool down.
Ms Butler said she had asked after Khan’s family and found him “fairly chatty” but thought the fact he was wearing a bulky jacket was “a bit peculiar”.
She said: “I remember seeing Usman in a puffer jacket and thinking it a bit peculiar.
“Obviously a lot more comes to light when you reflect afterwards. I remember seeing a base layer top. I remember thinking he wore the wrong clothes, it looked too tight.”
The inquest jury previously saw images of Khan wearing the coat – bought the day before, in a size larger than he would normally wear – at the Learning Together event.
He took it off once, but wrapped it around his waist to further conceal the fake suicide belt, the court heard.
Khan killed two and injured three others before being chased and disarmed on nearby London Bridge by three men armed with a fire extinguisher and a narwhal tusk.
He was then killed by police.
The inquests resume on Friday morning.