He declined to comment on reports by the BBC and Financial Times that the attacks were linked to the Russian state, but took aim at those who have tried to disseminate false stories in the wake of the incidents.
Conspiracy theories have circulated online about the assailants’ motives, shared by Russian-linked accounts and the far-right agitator Tommy Robinson.
Starmer told journalists: “There are many actors who want to divide our country and to cause conflict in our country. Some of the evidence that came out of trial speaks for itself, but there are wider issues here.”
He added there were “political leaders who are more than happy to indulge in tearing our country apart” as well as actors “from outside our country who are trying to find ways to exploit division in our country, to destabilize our democracy.”
“We need to be really clear in relation to that and we need to fight it at every twist and every turn,” he urged.
He specified that the actions targeting his property should be seen separately from the shots fired from a Russian ship at a British yacht, but acknowledged: “We have a Russia which is aggressive … We know that both Russia and Iran are responsible for proxy attacks in the United Kingdom and across Europe, and we have to be alert to that.”
The British PM highlighted “positive” work by leaders at the G7 culminating in a joint declaration vowing to boost military support for Ukraine and to strengthen sanctions against Russia.