BASEL, Switzerland, March 11 - Top central bankers see the world economy improving but are reluctant to predict when interest rates may have to rise to quell inflation, Bank of England Governor Sir Edward George said on Monday. Briefing reporters at the Bank for International Settlements after chairing a meeting which included officials from the U.S. Federal Reserve, the European Central Bank and the Bank of Japan, Sir George said: "We're seeing a recovery in the global economy. We don't know how strong it is going to be." "It is quite obvious that spring has come a little bit early this year," George added. "Behind it there was an uncertainty of whether spring would be followed by an agreeable summer." George stopped short of saying if he or his colleagues thought the recent round of interest rate cuts among major central banks had come to an end, or when rates actually may have to rise to quell inflation as the recovery gets underway. "It's ridiculous to say if this is the end of the cycle (of falling interest rates). I would mislead you if I pretended to know," he said. George said there were increasingly positive signs on the U.S. economy, the world's largest, where recovery was clearly under way now. In the eurozone, he said central bankers thought the trough was reached last year and a slow recovery had begun, expecting growth by the end of the year to be back to trend. George's assessment came after the European Central Bank left interest rates unchanged last week, but ECB President Wim Duisenberg said then that there were "good reasons to expect a return of economic growth to levels in line with potential towards the end of the year". George said the outlook for Japan, which has long been mired in recession, had also brightened somewhat. Central bankers expected the world's number-two economy to pick up speed gradually from the middle of the year, he said. Overall, central bankers gathering behind closed doors at the BIS were significantly more upbeat in their assessment of the world economy than at their last meeting two months ago, even though there were still risks to the outlook, George said. "On the whole I think it was -- without wanting to sound too buoyant -- probably the most hopeful discussion we have had for some considerable time," he said.