It is literally impossible to prove that the Russian interference in the UK 2016 referendum either had or had no actual impact on the outcome. The mere fact of interference as such does not point to any outcome. As Cambridge Dictionary defines it, interference is “when someone tries to involve themselves in a situation when their involvement is not wanted, not helpful, or not reasonable”. Russians did try to influence the outcome of the Brexit referendum, which means that they _interfered_ in it. But the impact of their attempts - either positive, neutral or negative - is beyond any discussion of the outcome and, again, impossible to establish. What is possible to investigate though - and should be investigated - is why the Tory governments covered up the Russian interference.