Russia would likely take up to 1.8 million wounded and dead over five years to fully capture four major Ukrainian regions, according to Gen. Sir Roly Walker.

The four regions in question are Donetsk, Luhansk, Kherson, and Zaporizhzhia, which are currently under partial Russian control.

Russian leader Vladimir Putin declared these four oblasts part of Russia's territory in September 2022.

Western estimates suggest Russia's casualty rate could be as high as 1,000 soldiers wounded or killed daily, with UK intelligence estimating over 500,000 troops lost.

The British military aims to double its firepower by 2027 and triple its capacity by 2030, with concerns that Russia could seek retribution against the UK for its support of Ukraine.