Document management software company Version One said it has proof that business people are missing out on opportunities, which they are genuinely interested in because their numbers have been blocked without their prior consent.
Catherine Murphy, Version One marketing manager, said: "The big problem is that of the 200,000 telephone numbers on our database, there's a quantity which have been registered with the CTPS without the necessary internal consent.
"For instance, some hospitals have registered all their telephone numbers with the CTPS, including the main switchboard number, preventing telemarketing calls to all staff at the hospital.
"Although the CTPS states that people who register a number need to have the authority to do so, who is policing this?"
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