TALKTALK  has said it will waive exit fees for some customers wanting to leave their contract - but only in cases where money has been stolen from their bank account as a direct result of the cyber attack.

In the "unlikely event" that money is stolen from a customer's bank account directly because of the attack - rather than as a result of a customer giving their information out - TalkTalk said it will look on a case-by-case basis to waive termination fees "as a gesture of goodwill".

Consumer group Which? has been urging TalkTalk to allow any affected customers who want to leave their contract to be able to do so without penalty.

TalkTalk reminded customers that criminals will try to dupe people into handing over their personal information with phone, email and text scams.

For example, TalkTalk said it will never call customers and ask them to provide bank details unless it has already had specific permission from the customer to do so.

:: How have customers been affected?

TalkTalk has said there is a chance that some of the following data may have been accessed:

Names, addresses, dates of birth, email addresses, telephone numbers, TalkTalk account information, credit and debit card details and/or bank details.

TalkTalk has said any credit or debit card details that may have been accessed had a series of numbers hidden, meaning they cannot be used for financial transactions. TalkTalk My Account passwords have not been accessed.

:: How many of TalkTalk's four million UK customers have been affected?

TalkTalk has not put a figure on this, but it said the number of customers affected and the amount of data potentially accessed is smaller than it originally thought.

:: What is TalkTalk doing to deal with the cyber attack?

It has contacted customers by email and letter and has worked to secure the website. It is working with cybercrime experts, the security services and police. It has contacted major banks so they can monitor any suspicious activity on customers' accounts and it has also shared details of the attack with the Information Commissioner's Office (ICO).

:: What can customers do?

Customers should monitor their accounts over the next few months and contact Action Fraud if they spot anything unusual on 0300 123 2040 or via www.actionfraud.police.uk.

If you are contacted by anyone asking for personal data or passwords, take all steps to check the true identity of the organisation.

:: Can I leave TalkTalk without being hit by an exit fee?

TalkTalk will only waive termination fees in cases where money has been stolen as a direct result of the attack.

For TalkTalk to consider a request to leave without a termination fee, the customer will need to meet the following criteria:

You have had money taken from your account without your consent and you have incurred a financial loss as a result; The money was taken on or after October 21 2015; You have contacted Action Fraud UK and obtained a crime reference number.

If you meet all three criteria, you can write to TalkTalk with the crime reference number and a copy of the proof of the fraud at: Crime Notification, The Legal Department, TalkTalk Group, PO Box 346, Southampton, SO30 2PW.