Police in Havering were called at 13:09hrs on Thursday, 20 August to a building site in Langton Gardens, Hornchurch to reports of a grenade unearthed by construction workers.
Officers attended and a safety cordon was established. A number of people from a nearby office block were evacuated as a precaution.
Specialist officers attended and were able to confirm that the grenade was no longer live and was likely a spent shell from either the first or Second World War.
The grenade was safely removed from the scene without incident and the site reopened at 14:55hrs.