Almost two months into Russia’s invasion of its neighbouring country, military analysts continue to express surprise at the strength of the Ukrainian resistance. Key strategic areas, including Kyiv and Mariupol, refuse to fall under increasingly heavy fire.

The UK Ministry of Defence (MoD) outlined the difficulty faced by Russian forces in its intelligence update yesterday evening, on April 19.

One difficult in judging Russia’s progress is a lack of understanding outside, and perhaps within much of the Kremlin of Putin’s war aims.

But the MoD report noted Russia was proving incapable of carrying out its clear objectives, including the taking of Mariupol.

It said: “Russia’s inability to stamp out resistance in Mariupol and their indiscriminate attacks, which have harmed the resident civilian populace, are indicative of their continued failure to achieve their aims as quickly as they would like.”

Putin yesterday gave Ukrainian forces in the southeastern port city hours to lay down their weapons or be killed.

His Defence Ministry ordered Ukrainians to leave a strategically important steel plant in the area “without any weapons and without ammunition”.

This came days after analysts predicted the city would fall into Russian hands “within hours”.

But many Ukrainian troops have held their positions and the fighting continues.

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This defence, it said, was aided by the “highly-motivated Ukrainian armed forces”.

But Russian troops have, the MoD added, been pushed back by a range of other challenges – some within and some outside of Moscow’s control.

The report said: “Russia’s ability to progress continues to be impacted by the environmental, logistical and technical challenges that have beset them so far.”

The environment has played a role since the beginning of the war, and, in fact, before the fighting even began.

Reports in January revealed the White House had recruited a team of weather experts to monitor conditions and suggest timings for a then potential attack, on the understanding a warmer-than-usual winter in eastern Ukraine had held off an advance because it prevented the ground from completely freezing over.

As the war continues, new reports suggest Kremlin insiders are becoming increasingly worried by the invasion of Ukraine and are growing concerned with Putin’s aims.

Bloomberg highlights that “a small but growing number of senior Kremlin insiders are quite questioning his decision to go to war”.