Westminster has ruled out holding an investigation into meddling by Russia in the EU referendum.

In a response published this morning, timed to coincide with the publication of a long-awaited report into Russian interference in UK democracy, the Government said an investigation is "not necessary". 

It comes despite harsh criticism by the Intelligence and Security committee (ISC) members that government officials ignored prior warnings, and decided actively to ignore the threat posed by Russia in the EU vote. 

Boris Johnson's official response to the Russia report states: "We have seen no evidence of successful interference in the EU Referendum.

"The Intelligence and Security Agencies produce and contribute to regular assessments of the threat posed by Hostile State Activity, including around potential interference in UK democratic processes.

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"We keep such assessments under review and, where necessary, update them in response to new intelligence, including during democratic events such as elections and referendums.

"Where new information emerges, the Government will always consider the most appropriate use of any intelligence it develops or receives, including whether it is appropriate to make this public.

"Given this long standing approach, a retrospective assessment of the EU Referendum is not necessary."

The decision has sparked criticism by SNP MP Stewart McDonald, the party's defence spokesman, who said: "It is clear that the Tory government deliberately failed in its duty to assess the level of Russian interference in the EU referendum, and the potential impact that had on the Brexit result - seemingly because it didn't want to know the answers. An independent inquiry must now happen.

“Despite the growing threat posed by sophisticated Russian misinformation campaigns, the report found that the UK government only ‘belatedly realised’ the level of threat after the DNC hack and leak operation. The Tory government clearly took its eye off the ball.

"During the election campaign, Boris Johnson claimed 'There is absolutely no evidence that I know of to show any interference in any British electoral event'. The report – which the Prime Minister had already read at that point - now makes clear that this is because the Tory government was not looking for it. This botched attempt at a cover up by Downing Street has been laid bare by the committee’s findings.

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"The UK government must now work with our international allies and set out how it will get a grip of Russian interference. Any narrow party-political attempt to use this report to stymie democracy in the UK would be unacceptable. We need a sober reflection from government and parliament, and a thoughtful way ahead. The public would expect nothing less."

The relationship between Downing Street and the ISC has been strained since former Conservative MP Julian Lewis was elected as chairman last week, after receiving votes from opposition politicians. The Prime Minister had nominated MP Chris Grayling for the post, and after his defeat Mr Lewis was ejected from the Tories. 

During this morning's press conference, Mr Lewis said: "This committee has been subjected to unprecedented delay and dislocation.

"This really must never happen again. As soon as normal relations are restored between this committee and the government, the better it will be for all concerned.

"Yet that prospect has not been helped by the Government refusing to tell us what was in the written ministerial statement about this Russia Report, which the government chose to table in the commons at 10.30 this morning to clash with the start of this event.

"Maybe I'm being unfair to them. Maybe they have another plan, maybe they're going to add to their written ministerial statement by making an oral statement on this subject perhaps tomorrow so that the Commons can have its say and ask it's questions. That would be a very positive sign. Let's hope it happens."