Police were called to Eastern Avenue in Romford late on Tuesday to reports four men in their 20s had been stabbed.
One man is reported to be in a life-threatening condition, as police continue their enquiries.
No arrests have yet been made.
Anyone with information is asked to call 101 quoting CAD8152/28May or call Crimestoppers anonymously on 0800 555 111.
The other three victims aren’t believed to be in critical conditions.
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