Butt, 27, was responsible for “conducting security searches” at Southwark Underground Station, the inquest into the terror attack, was told.
Eight people were killed when Butt, Rachid Redouane, 30, and Youssef Zaghba, 22, drove a van into pedestrians and stabbed others in the London Bridge area on 3 June 2017.
Jonathan Hough QC, for the coroner, told the Old Bailey how TfL had carried out a background check but that it “appeared not to have picked up on the Jihadis Next Door programme a few months previously”.
Butt had been fired from a number of jobs including the one at TfL after he took extended sick leave claiming that the standard issue shoes were hurting his feet.
He had planned to move to Syria to fight for ISIS in early 2015 but that his father-in-law Abdul Rehman-Butt had destroyed and a one way ticket to prevent him from traveling.
Later that same year, Butt met with the radical preacher Anjem Choudary.
Friend Hamza Raza told investigators: “He met Choudary when he had gone round to Butt’s home once during the Ramadan period.”
Mr Raza said Butt was energized in Choudary’s company and “like a lion out of a cage when Choudary was around.”
At least two friends, including Butt’s brother-in-law Usman Darr, told investigators that they had reported Butt to counter-terrorism officials but no record could be found of the formal reports.
The killer came to the UK in 1998 from Pakistan with his family on a visitors visa at the age of 8.
They were initially refused asylum but were granted indefinite leave to remain following an appeal in 2004.
Butt had worked at Topshop on Oxford Street in late 2008 and also as a cashier at a pizza takeaway shop around the same time.
Acting Detective Chief Inspector Wayne Jolley said after studying IT and business communication in 2009, Butt went on to work at a removals firm between late 2009 and early 2012.
His manager at Eco Movers told investigators that teenage Butt “was into a bit of gangsta rap and liked to smoke cannabis” and “liked to make out he was some type of east London bad man”.
Colleagues described him Butt as ‘polite, respectful, shy but also able to hold his own.’
He was made redundant from that job in March 2012 and moved onto Auriga Holdings, a company that managed KFC franchises in east London.
“Khuram Butt became increasingly strict in his Islamic faith,’ explained Mr Hough.
“A colleague of Khuram Butt’s had a discussion with him around the murder of Lee Rigby.
“Butt said it was an eye for an eye.”
He told the court that Butt married Zahrah Rehman in December 2013 and that when she suffered a brain aneurysm he was caring.
“She said that he provided regular care and that he was kind and considerate and dedicated towards her.”
The inquest heard Butt’s increasing radicalisation, much of which came through YouTube videos, changed his behaviour towards his wife and he started pushing Zahrah to allow him to have a second wife.
“The couple were already having issues with their marriage over Butt’s request to Zahrah for a second wife so she had moved out to her parents house,” explained DCI Jolley.
He told the inquest that Butt’s family became increasingly concerned with his behaviour after he was barred from a number of mosques for interrupting with the imams.
In July 2015, Butt was filmed for the Channel 4 documentary The Jihadis Next Door outside the Regent’s Park mosque praying in front of the black standard of ISIS.
“He felt that the British government was unfairly targeting Muslims with its terrorist laws,” explained DCI Jolley.
Butt could be heard on camera saying: “The government is extreme. They have killed the most people. They are the extremists.”
The inquest heard that Butt taught young children about the Quaran after being hired by head teacher Sophie Rahman at the Ad-Deen Primary School.
“He was teaching for two hours each afternoon, Monday to Friday. He took a group of about six or seven boys and girls around the age of eight or nine years old,” explained Mr Jolley.
Butt, Rachid Redouane, 30, and Youssef Zaghba, 22, were shot dead by police less than 10 minutes after their murderous attack began.
Christine Archibald, 30, Xavier Thomas, 45, Sebastien Belanger, 36, Kirsty Boden, 28, James McMullan, 32, Sara Zelenak, 21, Alexandre Pigeard, 26, and Ignacio EcheverrÃa, 39, were all killed in the attack.