The measure will be presented to Parliament on Wednesday, and would make it a criminal offence to support the organisation.
ADVERTISEMENTThe British government is set to add Russia's Wagner mercenary group to its list of terrorist organisations.
UK Home Secretary Suella Braverman UK is likely to introduce the measure to Parliament on Wednesday, according to British media.
"Wagner is a violent and destructive organisation that has acted as a military tool abroad for Vladimir Putin's Russia," the Daily Mail quotes Braverman as saying.
"While Putin's regime decides what to do with the monster it has created, Wagner's continuing destabilising activities only continue to serve the Kremlin's political purposes", she added.
The British Home Secretary has the power to "proscribe" an organisation that she considers to be involved in acts of terrorism.
This "proscription", which already applies in particular to the Islamic State group and the jihadist organisation al-Qaeda, makes it a criminal offence to support the organisation.
"Wagner has been involved in barbaric looting, torture and murder," Braverman told the Daily Mail.
"That is why we are outlawing this terrorist organisation and continuing to help Ukraine as much as possible in its fight against Russia", she added, noting that Wagner was also "a threat to global security".
In July, London had already announced sanctions against 13 individuals and organisations linked to Wagner in Africa, accusing them of war crimes.