HUTCHISON Whampoa and AT & T finally announced their long expected separation yesterday, with Hutchison selling out of the joint venture to market added value telephone services. AT & T plans to build on the foundations already laid to achieve a significant slice of the US$250 million a year forecast market for added value telecommunication services in the Asia-Pacific region by the end of 1997. No sum was given for the sale by Hutchison of its 51 per cent in Hutchison AT & T Network Services (HANS), which handles about 35,000 messages a day and has a market share of about $9 million. The regional managing director at the new company, AT & T EasyLink Services, Joseph Antonellis, said: ''We cannot give out the amount of money involved as this is a private transaction.'' He said the two sides broke up, having formed the joint venture in January 1991, because of differences in strategy. Hutchison wanted to concentrate on telephone and paging services in Hong Kong and China. AT & T was interested in providing added value services in stored and forward faxing, electronic mailing and electronic interchange in Hong Kong and throughout the Asia-Pacific region. Mr Antonellis said the parting of ways had been amicable and there was no legal action or threat of legal action hanging over either of the two former partners in this matter. The market for added value services being offered by EasyLink was growing in the region about 40 per cent year-on-year and this was expected to continue for two or three years. Last year, it was estimated the market was worth between $80 million and $90 million, of which the joint venture had some 10 to 15 per cent. In the future the group plans to be a leader in the sector with significant market share, but no partnership is likely to be formed in the near future. Meanwhile, Hong Kong will remain the hub and is expected to overtake Japan as a major revenue generator. Australia is the group's other major source of business. Mr Antonellis said the company had direct presence in Hong Kong, Japan and Australia, with representative presence in Taiwan, the Philippines, South Korea and Thailand. It planned to build direct presence in Singapore and Korea. China was also an important market to develop. AT & T said it had no plans, nor could it foresee plans in the immediate future, to list on the Hong Kong stock exchange. A spokesman did add there was nothing at present precluding them from applying for a listing, however. The products offered by EasyLink include an enhanced fax system which offers storing and forwarding, multi-destination and guaranteed delivery. It also has global messaging.