TalkTalk cyber-attack: Your views

Police are investigating a "significant and sustained cyber-attack" on TalkTalk website, the UK company says.

The phone and broadband provider, which has over four million UK customers, said banking details and personal information could have been accessed.

TalkTalk said potentially all customers could be affected but it was too early to know what data had been stolen.

Customers past and present have been sharing their views and experiences with the BBC. Here is a selection:

@poetryanne tweets TalkTalk has to do more than issue apologies:

C Allen, Mansfield, Nottinghamshire: I'm a long term and satisfied TalkTalk customer, but obviously concerned by the cyber attack.

TalkTalk have instructed customers to change their account password immediately, but the website is is down so it isn't possible.

Surely the safest way would be for TalkTalk to cancel online account customers passwords and post out new ones to their home address?

Andy Haworth, Preston, Lancashire: Whilst I'm not a current TalkTalk customer, I am a former customer who left back in June.

What worries me is TalkTalk haven't mentioned if this effects former customers, because I'm almost sure they will still be holding onto my data.

I suspect, that TalkTalk themselves probably don't know.

Thomas Kemp in London messaged on WhatsApp to say he has lost trust in TalkTalk:

Richard Baguley, Blackpool: This morning I had a conversation with TalkTalk's customer services.

Astoundingly, it appears some of the customer data was not encrypted. This seems particularly surprising following the Carphone Warehouse data breach over the summer.

I think it's possibly contrary to data regulations for them to hold data unencrypted.

I'm now waiting to hear what happens next.

Steve Tyler, Farnham, Surrey: While I appreciate that using broadcast media to spread word of this attack is probably the quickest means of informing the largest amount of people, I'm really disappointed not to have received a single piece of communication directly from TalkTalk as of this morning.

Even if it was just an email to acknowledge what had happened, it would at least provide some reassurance.

I do have sympathy for the company, but the fact that this is the second time it has been infiltrated in the past year leaves me with very little trust and I will probably be taking my business elsewhere.

@DoraExplorer47 tweets her disappointment:

Chris Wilkins, Farnborough, Hampshire: As a customer of TalkTalk I'm really annoyed that they let another attack take place!

I have been a customer for a year and this is the second time that there has been a security problem.

I considered leaving TalkTalk after the first time but as I was on a year's contract I thought I had to stay.

I don't know if I should cancel my account with them so that I'm not a victim of further attacks, or if I should stay with them now that the damage is done and they may be able to rectify anything that could happen to me as a result.

I don't think that there is anything on the internet giving impartial advice to TalkTalk customers at the moment.

Jonathan Westwood, Shrewsbury, Shropshire: I have received telephone calls over the past two months from people claiming to be TalkTalk representatives who clearly knew personal information about me. On each occasion when I asked who I was talking to and what number I could call them back on, the phone would go dead.

Stephen Hawley, Congleton, Cheshire: Obviously nothing to worry about as I haven't heard from them except for my monthly bill which arrived this morning!

Compiled by Andree Massiah