A teenage boy was stabbed to death in broad daylight in central London, Scotland Yard said.
Officers found the wounded 17-year-old less than three miles away from Parliament.
He was treated at the scene and later taken to hospital, London's Metropolitan Police said in a statement. He later died from his wounds.
“This awful attack took place in broad daylight in a busy part of central London," said DCI Andy Partridge. "A teenager with his whole life ahead of him has been taken away from his family who have been left heartbroken."
Appealing to the public for information, he added “We know that lots of people were in the area at the time and may well have seen what unfolded. We need them to do the right thing and get in touch right away with what they saw along with any images or moving footage captured before, during or after the attack.
“There is a college nearby and many young people would have been on their break. We are keen to hear from anyone with information that can help us build a clearer picture of what took place and bring those involved to justice."