Surbiton Telephone Exchange was to blame for Surbiton health centre patients being forced to wait yet more hours on the phone.
The problems were the latest in the phone fiasco which began the day the centre in Ewell Road opened on March 4.
A spokeswoman for the health centre said: "The issue on Tuesday morning was an external problem to the health centre to do with the telephone exchange which affected other areas."
She added that the issue on Friday morning was due to a software problem and the system should have diverted out-of-hours calls to the new non-emergency 111 number, but had not accounted for bank holidays.
The phone lines should be running normally today, she said.
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