The next 90 days of the war in Ukraine will be crucial for the future of European security and will be a fight for national survival for Ukrainian forces, an expert from a UK defence and security think tank has said.
In recent days Ukraine has made significant strategic gains, reclaiming territory in the east and south of the country.
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Ed Arnold, a research fellow at the Royal United Services Institute (RUSI), said that while Ukrainian forces have shown that their strategy is measured and calculated so far, the country's military would aim to exploit the knowledge of its own territory, such as natural points like rivers, to better exploit its position over the winter months.
Former infantry officer Mr Arnold said: "Ukraine will want to exploit its position at the moment as far as it can."
The defence expert predicts that the Ukrainian forces would use natural points like rivers where they are well defended to establish a "limit of exploitation".
This would reset the "contact line where they [the Ukrainian forces] want and then move their defence up and move HIMARS and the other defence systems that they have to get as much protection as they can.
"And basically, lock in those gains before the winter," he added.
The coming winter months will put Russia at a disadvantage. The Russian troops were initially expecting a four-day operation.
Watch: How HIMARS is helping Ukraine.
The invasion has dragged on for more than 200 days and the Russian morale is dwindling.
Moreover, because they were not planning for the operation to last this long the likelihood that they are well equipped for the coming winter months is low.
Speaking as an ex-infantry officer, Ed Arnolds said: "You need to stay warm. You need to be able to look after yourself both physically and mentally to be able to fight."
During the winter the priority will be replenishing new stocks of ammunition and pre-positioning them for the next counter-offensive.
Mr Arnold predicts that from March to November in 2023 it is possible that the counter-offensive could see the borders restored to what they were before 2014.