Sir Jeremy Fleming, the head of GCHQ, is set to use a rare public speech to say it increasingly looks like Russia’s President Vladimir Putin “has massively misjudged the situation” in Ukraine.

Speaking on Thursday during a trip to Australia, he will also say:

• Wagner, the private military company with suspected links to the Kremlin, is understood to be prepared to “send large numbers of personnel into Ukraine to fight alongside Russians”
• Wagner mercenaries would likely to be used as “cannon fodder” to try to limit Russian military losses
• Risks are greater for China than Russia of the two authoritarian states being too closely aligned with each other
• There are indications that Russian cyber attackers are “looking for targets” in the countries that oppose Moscow’s actions