There has been a surge in the number of wealthy Russians buying their way into the UK with special fast-track visas.

The number of Russians given "tier 1 investment visas", which are granted to those who invest at least £2m in the UK, is 69% higher in 2014 than over a comparable period in 2013.

A total of 169 of the visas were granted between January and September, with a steep increase occurring after after the West imposed sanctions on Russia following its annexation of Ukraine, reports the Sunday Times.

During the same period in 2013, 96 were granted, reveal Home Office figures.

Under the scheme, those granted the visa can apply for permanent residency after three years, if they invest £5m or more, or after two years with a £10m investment.

Under normal rules, those granted a visa must wait five years before they can apply for permanent residency, and a further year to apply for citizenship.

According to the Home Office website, Tier 1 visas usually take up to 30 days to be granted. However, applicants already in the UK can pay extra to get the visa processed within 24 hours.

With the ruble having crashed last week in response to dropping oil prices and western sanctions, lawyer Kamal Rahman, who handles applications at Mishcon De Reya told the newspaper that the number of applications is expected to rise.

"The thing our Russian clients are interested in is citizenship," she told the newspaper. "Investing the higher amount reduces the time from six years to five."

Last week, it was reported that increasing numbers of mansions and expensive properties were being bought up by Russians, with Knight Frank reporting that the number of super-prime London properties sold to Russians had risen by 13% in the six months leading to October.

Some of Russia's wealthiest oligarchs have lost millions in the ruble crash, with Roman Abramovich and Alisher Usmanov losing £400m between them in a 48-hour period.