Man admits stabbing new father Dr Jeroen Ensink in Islington

Dr Jeroen Ensink was killed metres from his home as he went to post cards announcing his daughter's birth

A man who admitted stabbing to death an academic outside his London home had a knife offence charge against him dropped six days before the killing.

Dr Jeroen Ensink, 41, was killed on 29 December as he left his Islington flat to post cards to friends and family to announce his daughter's birth.

Femi Nandap, 23, of Woolwich, admitted manslaughter by reason of diminished responsibility at the Old Bailey.

Three charges against Nandap had been dropped at court on 23 December.

The Crown Prosecution Service said it had "insufficient evidence to provide a realistic prospect of conviction" over charges of possession of two knives and assaulting a policeman

'Considerable public concern'

Dr Ensink, a lecturer at the London School of Hygiene and Tropical Medicine who was leading a project to improve health in Africa, was stabbed repeatedly by Nandap on Hilldrop Crescent.

After the academic did not return from his short errand, his wife Nadja left the family home and found the street outside cordoned off and blood-spattered cards strewn on the pavement.

Femi Nandap admitted manslaughter by reason of diminished responsibility

Nandap, who has a history of mental health problems, spoke only to confirm his name and enter his plea when he appeared via videolink from Broadmoor hospital.

Duncan Atkinson QC said the prosecution accepted the plea as it was "clear... there was an abnormality of mental function at that time".

Nandap, of Pett Street, had been charged with murder.

Dr Ensink was originally from Holland and had joined the London School of Hygiene and Tropical Medicine almost a decade ago.

At the time of his death he was leading a study in the Democratic Republic of Congo to understand how to control and prevent cholera.

The school's director, Prof Peter Piot, said Dr Ensink was "passionately committed to improving access to water and sanitation in countries where children continue to die needlessly".

Dr Ensink was found with stab wounds in Hilldrop Crescent in Islington

At an earlier hearing, Judge Charles Wide said there could be "considerable public concern" about why the three charges against Nandap had been dropped at the magistrate's court.

Julian Hendy of the charity Hundredfamilies, which helps families of those killed by people with mental health problems, said it was "another deeply distressing case of a... young family destroyed by the violent actions of a seriously mentally ill offender".

Nandap will be sentenced on 10 October.

Dr Jeroen Ensink was leading a study looking at how improvements in water supply could prevent cholera outbreaks