Rostelecom is Russia’s biggest telecoms company, with its 13m broadband subscribers and 10.9m pay TV customers and generates revenues of about £2.8bn a year.

BT Global provides cybersecurity, cloud computing and network services to large corporations around the world including Nestle, HSBC and Visa. 

However, the business has scaled back its business in Russia in recent years and only just 17 staff in the country. 

The revelations come as Marks & Spencer stopped shipments to franchise stores in Russia, Ikea closed its shops and factories, and Volkswagen halted the production of vehicles in response to war in Ukraine. 

Meanwhile, Vodafone called time on a 14-year relationship with one of Russia’s biggest mobile operators earlier this week. 

Vodafone had deepened its relationship with MTS at the end of January, but has since moved to suspend its “partner agreement” as Russia’s assault intensifies. 

The mobile titan had joined forces with MTS in 2008 to help drive innovation and bolster its consumer and enterprise arms. 

MTS has more than 80m mobile customers across Russia, Armenia and Belarus, as well as 9m landline, broadband and pay TV customers. 

BT declined to comment.