He was held on suspicion of offences under the Computer Misuse Act, following a major breach of the telecoms firm's website last week.

Police are now searching his home in County Antrim in Northern Ireland.

TalkTalk bosses said they shut down their site last week following the "significant and sustained" attack in which customer details may have been stolen.

On Friday it said it may have been the target of a ransom demand by the hackers.

The company's four million customers are being asked to check their accounts for any suspicious activity "over the next few months" and change their passwords.

The breach is the third in a series of cyber attacks that have affected TalkTalk customers.

In August, the firm revealed its mobile sales site was hit by a "sophisticated and co-ordinated cyber attack" in which personal data was accessed.

In February, customers were warned about scammers who managed to steal thousands of account numbers and names from TalkTalk's computers.