TOKYO, Dec 25 (Reuters) - Yields on some Japanese government bond futures drifted higher on Friday in holiday-thinned trade after weak results from a Bank of Japan debt buying operation pushed down futures prices. Yields were also supported by a sense of relief after Britain and the European Union agreed a free trade deal, averting economic turmoil at the year’s end - the deadline for Brexit. Benchmark 10-year JGB futures fell 0.03 point to 151.95, with trading volume of 8,156 lots. The 10-year JGB yield fell 0.5 basis point to 0.010%. The 20-year JGB yield rose 0.5 basis point to 0.390%. The 30-year JGB yield climbed 0.5 basis point to 0.625%, but the 40-year JGB yield held steady at 0.665%. At the middle of the yield curve, the five-year yield rose 0.5 basis point to minus 0.115%. At the short end, the two-year JGB yield was flat at minus 0.130%. (Reporting by the Tokyo markets team Editing by Shri Navaratnam)