A fourth person has been arrested in connection with the alleged cyber breach against the telecoms provider TalkTalk.
Detectives from the Metropolitan Police Cyber Crime Unit (MPCCU) and officers from the National Crime Agency (NCA) searched a property in Norwich last night.
A 16-year-old boy was arrested at the address on suspicion of violating the Computer Misuse Act. He has been bailed until March 2016 pending further investigations.
This brings to four the number of young men arrested in the past week in connection with the breach. The investigation is clearly moving very quickly and ranging over much of the UK, with arrests having been made in Northern Ireland, Feltham in London, Staffordshire and now Norwich.
They have ranged in age from 15 to 20.
TalkTalk has said that the breach was less severe than initially thought, but has admitted that it lost as many as 21,000 unique bank account numbers and sort codes, 28,000 obscured credit card numbers, 15,000 customer dates of birth and 1.2 million customer email address, names and phone numbers.
Chief executive Dido Harding has said the company is writing to all affected customers to spell out what information has been accessed.