US Senators investigating Russian interference in the 2016 presidential election are renewing their focus on the activities of Russian oligarchs based in Britain.

US congressional investigators say they are particularly interested in interviewing alleged associates of Russian Oligarch Oleg Deripaska, who is known to have close ties with Russian President Vladimir Putin.

As part of its ongoing investigation into Russian meddling in the 2016 election campaign, the US Senate Intelligence Committee has now written a formal letter to a London-based security consultant requesting his presence in Washington to give evidence.

In the letter, a copy of which has been seen by The Telegraph, the bipartisan committee of US Senators wants British-based security consultant Walter Soriano to attend a special closed session in Washington to answer questions about his alleged association with Mr Deripaska, who has consistently denied any wrongdoing, as well as other key figures named in its Russian investigation.

The committee also expressed an interest in Mr Soriano’s possible links with two former MI6 officers, Christopher Steele and Christopher Burrows, who were responsible for producing a highly damaging “dossier” on US President Donald Trump’s alleged ties with Russia.

The committee has asked Mr Soriano to give oral evidence in Washington as well as producing “all documents and records, including hard copies or electronically stored information” relating to any dealings he may have had with a number of key figures in its Russia investigation.