Russian intervention in Brexit

This tweet, noted this exchange (4 mins in) from 21 March 2018 with Senator Mark Warner, top Democrat on the Senate Intelligence Committee in which he says:

Not only Russian attempted interventions in our elections but attempted Russian interventions in the French elections, observations they intervened in the Spanish Catalan elections, the British have come and visited us now because they’ve seen Russian intervention in terms of the Brexit vote.  We in western democracies have to be on our guard.

My emphasis.  Again, perhaps something for the BBC to follow up on?