Police were called by London Ambulance Service at 2.08pm on Friday, 9 April, to a report of a woman attacked with an axe inside a residential address in Princes Road, Ilford.
Officers attended along with paramedics from London Ambulance Service.
A woman, aged in her 50s, was found seriously injured. She was treated at the scene before being taken to hospital where she remains in a critical condition.
A 47-year-old man was arrested at the scene on suspicion of attempted murder. He has been taken into custody where he remains.
A crime scene remains in place and urgent enquiries are ongoing to establish the circumstances.
A number of suspects are believed to have left the address prior to the arrival of police. Detectives are appealing for any witnesses, or anyone with dashcam footage from Princes Road and the surrounding area on Friday afternoon, to call police on 101 quoting reference 3935/09Apr.
To remain anonymous, please contact Crimestoppers.
At this early stage, it is believed that the incident is primarily domestic in nature. The woman and the man arrested are known to each other. Enquiries continue.