The emergency services rely on the customer database of phone companies in situations where a 999 caller is not in a position to give their address or is cut off.
Which? magazine says Cable & Wireless's database has been giving 999 operators incorrect addresses or no address at all.
![[ image: width=150]](/olmedia/220000/images/_222917_database.jpg)
The magazine, which is owned by the Consumers' Association, says if operators cannot find an address using the database they have to contact the telephone company directly which can waste vital minutes.
Phone company records are also used to help track down hoax and nuisance callers.
As a result of the proliferation of domestic telecommunications companies operators may have to deal with dozens of databases.
Which? said 999 operators had suffered problems with Cable & Wireless's database on addresses all over the UK.
A Which? spokesman said: "In one case an ambulance responding to a caller suffering a heart attack was sent 17 miles in the wrong direction.
"By chance another customer's address was found to be more than two years out of date."
The magazine says at least one police authority has complained to the telecoms watchdog, Oftel.
Scores of addresses missing
Which? said over a three-week period this year more than 250 addresses for 999 callers were logged as missing from the database.
The information was sent to Cable & Wireless but two weeks later only 16 of the addresses had been added.
Which? Editor Helen Parker said: "The company is putting people's lives on the line because of its inability to keep its records correct.
"This is totally unacceptable."
Cable & Wireless said it had become aware of eight incidents where incorrect or missing address information had affected the service.
A spokesman for the firm said: "Paramedics and police are not being sent to wrong addresses now.
"This all happened last summer and we acted immediately to install new technology and set up a special hotline for operators.
"I don't believe we are putting lives at risk now as we have taken action to put in a back-up system."
He said: "We make sure that our information is as accurate as possible and are aware that 999 operators rely on this database."
Oftel is planning to visit a Cable & Wireless call centre to assess the situation.
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Cable & Wireless
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