Al-Noor Ramji told delegates at the Gigaworld IT conference in Lisbon that BT needs to keep pace with Google, which has " morphed" from a search engine into a business straddling the consumer technology area.
"We see Google as our biggest threat," said Ramji. "They don't mean to, it's almost incidental."
He acknowledged that Google comes from a "different world" but is expanding fast to meet consumers' needs.
However Ramji claimed that BT "can do anything Google can do", hinting that the telco would move beyond its traditional role as telecoms supplier.
"I've learned that technology is the easiest thing to do," he said. "The transformation of the company is most important."
Among the challenges facing BT, according to Ramji, is its expansion into television over IP with BT Vision.
Analysts were cautious about Ramji's statements, however. "I think he's a little bit ahead of his time," said Lars Godell, of industry researchers Forrester.
"I give him credit for thinking ahead and being proactive about competitive threats, but is the threat realistic? Google doesn't see BT as a competitor.
"Consumers still need to pay for bandwidth. That's the business of a telco, and I don't see Google becoming a full service telco."
Likewise, Godell does not see BT becoming a full service content provider. " The skills needed to be successful in content are so different from those needed for telecoms," he said.
"It will take five to 10 years before those value-added services will become more important [than providing bandwidth] to a telco's revenue stream."
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