TalkTalk customers whose private data could have been accessed in a cyber-attack should think carefully about what information they provide to anyone claiming to be from the company, a cyber security expert has warned.

Manchester University's Daniel Dresner said the hackers could contact customers while posing as TalkTalk in order to extract more details.

"Think whether what you are saying is exactly the kind of information which would open up your bank account....and think 'actually, these companies don't ask me for that sort of information'," he said.