CENTRAL BANKS BUY DOLLARS FOR YEN IN LONDON The Bank of Japan intervened to stem strong yen rises against the dollar during London trading this morning, dealers said. The Bank of Japan here declined comment. The Bank of England was also rumored to be buying dollars against the yen this morning but it also declined comment. Dealers said the intervention halted a sudden late morning drop to a low of 148.65 yen, holding the dollar steady until midsession at about 148.80. The Bank of England was strongly rumored to have intervened on behalf of the dollar against the yen yesterday, but it gave no confirmation. Overnight reports from Tokyo said that the Bank of Japan was aggressively supporting the dollar, but failed to push it back to the perceived target level of 150 yen. Selling during the London trading morning was largely attributed to Japanese institutions. Dealers here were loath to quantify the scale of Bank of Japan action this morning. One U.S. Bank trader said it could have been up to 500 mln dlrs, but said this was largely a guess.