Foreign banks are making little progress in restructuring talks with privately-owned Russian companies on tens of billions of dollars in debt, blocking new flows of credit into the Russian economy, a senior western banker said on Tuesday.

Hans-Jörg Rudloff, chairman of Barclays Capital, said “unconstructive” positions being taken by Russian oligarchs on restructuring huge debts built up in the pre-crisis boom years were putting the brakes on new foreign lending.