TalkTalk has lost an appeal against a 1,000 fine imposed as a result of a data breach it suffered last year.
The Information Commissioner's Office (ICO) fined the telco for not reporting the breach within 24 hours after discovering it, but TalkTalk appealed.
Information tribunal judge Angus Hamilton wrote in his decision: "The sole issue in dispute in this case is when TalkTalk could rightly be said to have detected' the personal data breach or to have acquired sufficient awareness' of the breach."
A TalkTalk customer (A) first noticed the breach when they accidentally found they had access to another customer's (B) personal data on 16 November 2015.
Customer A phoned B to notify them, and B subsequently phoned TalkTalk about the breach later that day, before following up with a letter on 18 November, and informing the ICO.
When the ICO wrote a letter to TalkTalk about the breach on 20 November, TalkTalk's CISO, Mike Rabbitt, replied to acknowledge he had read it.
Rabbit then wrote to the ICO on the 27 November to say TalkTalk was investigating the incident, but had not confirmed whether a personal data breach had occurred. TalkTalk did not notify the ICO that a data breach had occurred until 1 December.
TalkTalk appealed against the subsequent 1,000 penalty, arguing it had only acquired "sufficient awareness" of the breach after concluding its own investigation on 30 November.
However, the tribunal found that the customer's letter gave sufficient detail to prove that a breach had occurred, and that TalkTalk could not come up with another explanation for the incident other than a personal data breach.
