The TalkTalk hack is much smaller than everyone first thought

TalkTalk on Friday radically revised down the number of customers it says have been hit by a recent cyber theft of personal data.

The internet and phone provider says in a statement on Friday that just 156,959 people are affected by the hack, down from a previous estimate of 1.2 million and an initial assessment of 4 million.

Out of this total, 15,656 had their bank account and sort code assessed. 28,000 credit and debit card numbers were also taken, but TalkTalk says in all of these cases numbers were obscured and the data was not kept with other identifying information like names and addresses.

TalkTalk's stock plummeted after it was hacked was hacked for a third time late last month following a "significant and sustained" cyber attack that was initially thought to be the work of Russian jihadis. Two teenage boys from Northern Ireland and West London have since been arrested in connection to the hack.

TalkTalk says in Friday's statement:

It was a difficult decision to notify all our customers of the risk before we could establish the real extent of any data loss. We believe we had a responsibility to warn customers ahead of having the clarity we are finally able to give today.

We have now contacted all customers who have had financial details accessed, reiterating our advice on what to do to keep themselves safe. The financial information accessed cannot on its own lead to financial loss. We will be contacting all other affected customers in the coming days.

TalkTalk says it won't contact any of its customers asking for financial or personal information, so watch out for scam calls. TalkTalk and the Metropolitan Police are still investigating.