China has hit out at the UK and other western nations for “groundless and irresponsible” accusations that it was behind major “systematic cyber sabotage”.

Foreign Secretary Dominic Raab said on Monday that Chinese state-backed groups were responsible for a “reckless” attack on Microsoft Exchange servers earlier this year.

Widespread frustration was shared by the US, Canada, EU, Australia, New Zealand and Nato, who all called for an end to such behaviour.

Officials claim the attack was highly likely to enable “large-scale espionage”, including acquiring personal information and intellectual property.

If the UK side is serious about cyber security, it should not be indifferent towards, and still less an accessory to, such abuse of technological advantage and unscrupulous, large-scale and indiscriminate tapping and stealing of secrets against countries across the world, including its allies

At least 30,000 organisations around the world have been affected.

The Chinese embassy in the UK said the claims are a “sheer fabrication and slander”.

“The Chinese side is gravely concerned and strongly opposed to this,” a spokesperson said.

“We call on the UK side to immediately stop echoing the groundless and irresponsible accusation against China.

“China is a staunch defender of cyber security and a main victim of cyber thefts and attacks.”

China also pointed the finger at the US for being involved in cyber theft and surveillance, while accusing the UK of “double standards”.

“If the UK side is serious about cyber security, it should not be indifferent towards, and still less an accessory to, such abuse of technological advantage and unscrupulous, large-scale and indiscriminate tapping and stealing of secrets against countries across the world, including its allies,” the spokesperson continued.

“On cyber security issues, the UK and a handful of other ‘like-minded countries’ are applying double standards and playing the trick of a thief crying ‘Stop thief!’. We are firmly opposed to this practice.”

Officials at the National Cyber Security Centre (NCSC) are “almost certain” that the compromise was initiated and exploited by a Chinese state-backed actor and it is “highly likely” that a group called Hafnium is associated with the Chinese state.

Foreign Office minister James Cleverly later doubled down on the UK Government’s claims in response to an urgent question in the House of Commons.

He told MPs there was “widespread credible evidence” the Chinese government was behind the attack, adding: “The Chinese government must end this systematic cyber sabotage and can expect to be held to account if it does not.”

Conservative former leader Sir Iain Duncan Smith added he believes he has become the target of a “direct threat” from the Chinese government.

He said: “I understand now there is intelligence from the Five Eyes sources that there is now a very active and direct threat from the Chinese government aimed directly at the co-chairs of the Interparliamentary Alliance on China.

“Some of these co-chairs, of which I am one, have now been warned by their intelligence services in receipt of this that they should be very careful and that they will be supported.”

For Labour, shadow foreign secretary Lisa Nandy said: “The truth is the Government is unable to send a clear, coherent message to Beijing because it’s still arguing amongst itself.”

The SNP’s Alyn Smith added: “I would applaud the fact there will be sanctions, there will measures, but I really would like to hear what they are because the somewhat homeopathic approach to date really doesn’t seem to have had much of an impact on stopping anything.”

Conservative former minister Tim Loughton backed the SNP’s comment, adding: “Homeopathic remedies when you’re dealing with a psychopathic regime does not work. We’ve had industrial-scale human rights abuses.”