A man has been taken into police custody following an early morning raid at a location in east London.
A spokesman said detectives investigating the terror attack on London Bridge and Borough Market conducted a search of a property in Ilford.
A 30-year-old man was arrested on suspicion of commissioning, preparing, or instigating acts of terrorism during the search.
Scotland Yard said he had been taken to a south London police station to be questioned.
The news of the arrest comes as the security services and police forces face questioning related to how they monitored the three attackers prior to the incident.
Seven people died and dozens were injured after Youssef Zaghba, Khuram Butt and Rachid Redouane drove a van into pedestrians on London Bridge and proceeded to stab multiple bystanders in Borough Market.