The UK has been gripped by the disappearance of Sarah Everard – who vanished while walking home from a friend's house in southwest London, six nights ago.
The 33-year-old was supposed to have returned home to nearby Brixton around 50 minutes later, but she has not been seen since.
There has been a huge effort to find her in the past week, but overnight police revealed they had made an arrest – of a serving Metropolitan Police officer – in connection to the case.
Metropolitan Police Assistant Commissioner Nick Ephgrave said: "The arrest this evening is a serious and significant development.
"We will continue to work with all speed on this investigation but the fact that the arrested man is a serving Metropolitan Police officer is both shocking and deeply disturbing.
"I understand there will be significant public concern but it is essential that the investigative team are given the time and space to continue their work."
The Met said a woman had also been arrested at the same location on suspicion of assisting an offender and also remains in custody at a London police station.