LONDON is winning trade in major Hongkong blue-chip stocks at an accelerating pace, according to new figures. Hongkong's share of the prime blue chip, Hongkong Telecommunications, has now declined to less than 25 per cent, the figures show. A regulatory spokesman said trading of Hongkong Telecom American depository receipts in New York over the past year had ranged from a high of 58.5 per cent of total global trading in September to a low of 24.8 per cent in March. ''The more successful we appear to be in raising market turnover the more we seem to be losing, as our market share in blue-chip trading is evaporating,'' said a spokesman. Many institutions prefer to trade stocks offshore to avoid Hongkong stamp duty and levies linked to the regulation of the stock market. Another factor is that commissions in Hongkong are fixed, while elsewhere they are negotiable. London's share of trading in seven key stocks listed in Hongkong has risen between 34.5 per cent and 293.9 per cent between November last year and February. It amounted to 12.61 per cent of total turnover in Cheung Kong (Holdings) at the beginning of the period and stood at 29.11 per cent by February. For China Light and Power Co, London's share of trading rose from 25 to more than 40 per cent. In the case of Dairy Farm International Holdings, the rise of London share was more precipitous, from 24.85 to 44.35 per cent. Hang Seng Bank has been the focus of overnight trading with London taking only four per cent of total turnover at the start of the period. By February, market share was up to 16 per cent. Hongkong Land Holdings, Hongkong Telecom and HSBC Holdings also saw turnover losses to London; by February the share of trading accounted for by London was 32 per cent, 35.75 per cent and 62 per cent respectively. The significant London share of trading in HSBC was to be expected, said a regulator, as turnover overnight had risen constantly since the bank's change of domicile to Britain and takeover of Midland Bank. The regulatory spokesman said the loss of turnover activity to London and New York was of deep concern and the subject of discussions with the Government and Inland Revenue authorities to find ways to cut Hongkong trading costs.