Teddy Kelt, 20, from Bower Close, Romford, pleaded guilty to three counts of robbery and three counts of attempted robbery at Inner London Crown Court.
He also admitted to two public order offences, two counts of possessing a knife or bladed article in public, and a charge of common assault.
On December 4, 2024, Kelt approached a 22-year-old man on the platform of Mile End Underground station.
He threatened the victim, saying he had a knife and would stab him if he called for help.
The victim handed over his mobile phone to Kelt, who then searched his pockets, slapped him, and pushed him to the ground before leaving.
The following day, Kelt sat next to a 16-year-old boy on a Jubilee Line train.
He questioned him about his phone before revealing a machete and demanding the boy hand over his phone.
Kelt was involved in three separate attempted robberies on December 6, 2024.
He sat opposite a 21-year-old man and a 13-year-old boy on a Northern Line train, asking about the man’s watch and making threats.
He then approached a 19-year-old man about his headphones, threatening to stab him for his phone.
He dropped his knife on the floor in front of the man before leaving the train.
The following day, Kelt approached another man at Finchley Central Underground station.
He asked to use the man’s phone to call a friend, then followed him onto the train, where he showed him the handle of a knife in his waistband, threatening to kill him.
The victim handed over his phone, laptop, and iPad out of fear.
Kelt also demanded the victim get off the train at Tufnell Park with him, where he robbed him of his headphones and rucksack.
Later that day, Kelt attempted to rob a 17-year-old of their phone on an Elizabeth Line train, again threatening to stab him.
When other passengers intervened, Kelt attempted to punch one of them.
Not long after, on another Elizabeth Line train, Kelt tried to rob another man of his phone and said he would “slash his neck” before walking off.
Over the course of these four days, Kelt robbed three people of items worth nearly £4,000.
He is already serving a 3-year-and-9-month prison sentence for three additional robberies, two more attempted robberies, two counts of possessing Class C drugs, and possessing a corrosive substance in a public place.
These crimes took place at Ilford, Gidea Park, Goodmayes, Bexleyheath, and Seven Kings between November 29 and December 9, 2024.
Officers identified Kelt after a robbery at Gidea Park on December 9.
They recognised him in CCTV footage and found him in the garden early in the morning, wearing a stolen coat with several stolen phones in his home.
Detective Sergeant Steven Ridpath-Mitchell said: “Kelt is an exceedingly violent and dangerous individual who spent four days mostly targeting teenagers, threatening them at knifepoint, for his own benefit.
“I hope that his guilty plea provides some sense of closure to the victims after he put them through such an awful ordeal.
“He’s shown no remorse for his actions, either refusing to be interviewed or providing no comment or reply.
“The threats that he made against innocent commuters and the violence he used to rob them of their belongings is frankly sickening.”
Kelt is due to be sentenced at Inner London Crown Court on October 16, 2025.
