The experience of UK and US forces in Iraq should show Russia that occupying a sovereign country is “the hardest bit”, Britain’s defence secretary has said.

       Ben Wallace predicted “years” of resistance from the Ukrainian people even if Vladimir Putin succeeds in seizing the cities currently under heavy bombardment from Russia forces.

       “I think this is going to take a very, very long time,” he told LBC. “I think the lessons for everyone are in history, Chechnya, the Soviet Union in Afghanistan, invading is [the] easier bit, the hardest bit is occupying.”

       Mr Wallace said: “We learned that as a coalition in Iraq. And remember, in Iraq a large part of population did want us there. And it still meant that we lost a few hundred people as a coalition invading Iraq. We lost thousands in the following ten years occupying Iraq.”

       He added: “Well, imagine what that’s like in a country with Ukrainian fighters. 44 million people well supplied with defensive equipment, and none of them want you there. That’s where Russia will pay the price.”

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       The defence secretary warned that Putin knows “no limit” and will use indiscriminate carpet bombing against Ukrainian cities as his forces close in on the capital Kyiv and lay siege to the country’s population centres.

       Russian troops have entered Ukraine’s second city Kharkiv following days of intensive bombardment, but Mr Wallace said Mr Putin’s forces did not yet control it.

       The Ministry of Defence said the latest intelligence suggested Russian forces had reportedly moved into the centre of Kherson in south Ukraine. Artillery and air strikes have targeted built-up areas in Kyiv, Kharkiv, Mariupol and Chernihiv.

       But Mr Wallace said the advance of Russian forces continued to be slowed by a combination of overstretched logistics, poor morale and brave resistance by Ukrainian fighters.

       This map shows the extent of Russia’s invasion of Ukraine

       (Press Association Images)

       “The Russians are considerably behind their schedule, by days not hours, and that leads to stresses on their logistical supply chains,” he told the BBC. “That’s why you have seen some of these columns fairly grind to a halt.

       There was “huge amounts of low morale in the Russian forces, we’ve seen lots of surrenders … They have also been surprised by the strength of the Ukrainian resistance.”

       Mr Wallace again rejected calls for RAF jets to enforce a no-fly zone, warning it would trigger a Europe-wide conflict. Asked on LBC if he was afraid of Vladimir Putin, he said: “I’m not afraid of Putin.”

       Asked why the UK was not taking more direct action against Russia, Mr Wallace said: “Well, I don’t want a war across the whole of Europe. You know, ask your callers, do they want a nuclear armed Russia to be at war with all of us, across Europe and Atlantic?”

       The defence secretary earlier suggested the Russian president “doesn’t really care” about the impact of sanctions because there is a sense of “pride” in what his people can withstand.

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       The minister said: “When I went to the Russia myself, the Russian ministry of defence they were very clear the Russian people could suffer greater than mine or greater than Europeans – ‘We can’t be harmed by sanctions’.”

       Mr Wallace added: “I think he’s about to be shocked. This is the 21st century. Russian people, like European people, don’t want to go through what they’re about to go through.”