Relations with Russia are the biggest problem facing Georgia a year after a bloodless coup ushered in a reform-minded leadership, Prime Minister Zurab Zhvania said. The chief bones of contention are the status of Russian military bases on Georgian soil and Moscow's support of the leadership of two breakaway regions, mountainous South Ossetia and the Black Sea region of Abkhazia. "Despite a quite intense dialogue which continues still, there are too many question marks in our relations," he told Reuters in an interview late on Friday after a visit to London to woo foreign investors. Zhvania called Georgia's former colonial master "extremely irresponsible" for the direct and indirect ways in which he said it was undermining his country's authority in the two regions. But he also said talks were under way on an agreement aimed at improving ties, expressing hope it would be finalised by the end of January. South Ossetia and Abhkazia broke away from Tbilisi's control after the breakup of the Soviet Union in 1991. --More 2014 Local Time 1714 GMT