Chief executive Dido Harding said it had been a “challenging time” for the broadband company’s four million customers.

“We obviously saw an immediate bounce in customers wishing to cancel their direct debits and to churn, but we saw those leading indicators come back down quite quickly,” she said, before adding, “The early signs are encouraging that we are doing the right thing.”

Ms Harding took to the airwaves to warn TalkTalk’s customers that personal details, including bank account and credit card numbers, could have been stolen within hours of the attack on October 21.

The cost of the TalkTalk hack: £30m to £35m https://t.co/rJtGlGIvNn pic.twitter.com/GOrbRrJovO — Financial Times (@FT) November 11, 2015

Only 157,000 customers were affected, it later said.

She was positive about TalkTalk’s prospects, and she said, notwithstanding the attack, earnings would rise in the second half.

TalkTalk yesterday said revenue for the six months to the end of September grew 4.7% to £912m pounds, helped by customers taking more services like mobile and television.

Core earnings, however, fell 18% to £90m, and the company’s broadband base fell by 80,000 after it disconnected 72,000 customers for non-payment.