A 36-hour outage at UK Internet service provider Fasthosts.co.uk has left many customers angry and planning to transfer their business to other hosting companies, even though the ISP blames BT for the problems. Websites hosted by the company were inaccessible on 29 and 30 May, and other customers were left without email services. Fasthosts is blaming the outage on a denial-of-service attack on a BT router in Reading. Although the problem has now been fixed, users are criticising Fasthosts for what they claim is the latest in a series of glitches which could damage their businesses. One Fasthosts customer, who hosts and designs Web sites, said he was still assessing the damage. "About two dozen [of our] sites were affected. They went down on Tuesday morning and didn't start to come back until the following afternoon, and we still didn't have FTP access until Wednesday evening." "I think the damage to our company is substantial. We're still working out the extent of the damage, and we'll have to see what our clients say," he said. "We're already in the process of moving the more heavily-used sites to other hosting services". Other users were yet more critical. One angry customer wrote in a newsgroup that he was "probably in danger of going out of business". Other posters suggested that disgruntled customers should get together and sue Fasthosts. According to one customer who joined Fasthosts two months ago, his email accounts, ftp access and website uptime has been "a liability to say the least" -- and he is now looking to transfer his business elsewhere. No-one at Fasthosts was available for comment on Thursday, but it seems that the ISP is blaming this week's problems on BT. According to reports, chief technical officer John Davies has claimed that it took BT twenty-four hours to detect a denial-of-service attack on a router at Reading. Davies has said that the only way that Fasthosts was at fault was in using BT. For complete business coverage, see ZDNet UK's Enterprise Channel. For complete small-business coverage, see Technology for Your Business. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Telecoms forum. Let the editors know what you think in the Mailroom. And read other letters.