Putin's demands would be bitter blow to Ukraine and could even lead to Zelenskyy's removal | Michael Clarke analysis

Russian President Vladimir Putin reportedly demands that he be given control of the whole of the Donbas as part - and only part - of his price for any peace deal with Ukraine.

The area referred to as "the Donbas" consists of two regions. Russian forces currently occupy almost all of one of them - Luhansk - and about 70% of the other - Donetsk.

The Donbas is historically an important industrial area of Ukraine, where its coal mines and heavy industries are located, as well as many of its old arms manufacturing plants from the days when Ukraine was part of the Soviet Union. The 30% of Donetsk that Ukrainian forces still hold, and would be required to give up under Mr Putin's demands, are very important to it for a number of reasons.

Follow latest: Ukraine war live updates Politically, it is not lost on all Ukrainians that Russia's 2014 takeover of parts of the Donbas (about 30% of the territory by the end of that year) began in the city of Sloviansk in the northern part of the unconquered Donbas. The Ukrainians liberated that city from Russian-backed forces and have held onto it since, and paid a high price in lives and money to keep it free.

The same applies to the other cities and villages still under Kyiv's control in Donetsk. It would be a bitter blow to Ukraine, and possibly even precipitate the removal of Volodymyr Zelenskyy as president - to give up to Russia territory that Ukraine has fought so hard to retain for the last 11 years.

But this area also has an immediate strategic importance for Kyiv. The four significant cities in this area form a 50 to 60km "belt" of strong fortifications.

Even the Russian military refer to Sloviansk, Kramatorsk, Druzhkivka and Kostyantynivka as the "fortress cities" and all the villages and settlements between them are well-defended, making best use of the topographical features on which they are situated. Read more:Mapping the land Ukraine could be told to give upTalks will be no repeat of Oval Office meltdown - here's why If Ukrainian forces had to give up these strong positions they would not be able to withdraw westwards to other defensive positions anything like as strong.

In short, they would be ceding their best defensive positions to Russian forces who could then use them as a springboard for further attacks westwards towards the Dnieper River, which the Ukrainians would struggle to defend so easily. The fact that Russian forces have been geographically close to Sloviansk and Kramatorsk for so long without being able to take them tells its own story of the effectiveness of the "fortress cities" to hold out against Russian attacks.

Not least, there would be some advantage to Russia in gaining access to mineral fields across that part of the Donbas which incudes workable, large deposits of lithium and titanium non-ferrous metals, and also some large rare earth deposits running in a north-south geological strip along the border between Donetsk and the neighbouring region of Dnipropetrovsk. Doubts over the value of Putin 'security guarantees' Some US officials have spoken about the possibility of obtaining credible security guarantees from Russia in the event that Ukraine agrees to Moscow's terms.

It is fair to say that there is near-unanimous opinion, both among the public in Ukraine and (with only a couple of notable but minor exceptions) among political leaders in Europe, that no guarantees Mr Putin might offer would be worth anything. His record in European security matters since he took power in Moscow in 1999 is of continual bad faith, deception, and treaty-breaking.

Russia guaranteed Ukrainian security in the Budapest Agreement of 1994 and then went on to conclude a Friendship Treaty with Ukraine in 1997 - but broke both of them by its first two invasions of Ukraine in 2014. The Minsk Agreement and then a later "Minsk II.