A man arrested in connection with the cyber attack on telecoms company TalkTalk has been released on bail.
Metropolitan Police say the 20-year-old has been bailed to attend a police station in March pending further inquiries.
The man was the third person to be held in relation to the alleged data theft and was being held on suspicion of offences under the Computer Misuse Act.
Two teenagers - a 16-year-old boy from London and a 15-year-old boy County Antrim in Northern Ireland - had already been arrested over the attack when the 20-year-old was detained on Saturday.
They have since been bailed.
TalkTalk said it had been subjected to a "significant and sustained" attack on its website on October 21.
It led to fears that millions of people may have had their bank details stolen, although the firm has since said the data hacked was much less than originally suspected with fewer than 21,000 unique bank account numbers and sort codes accessed.
The data breach is the third cyber incident affecting the telecoms giant in the past year.