Morrisons has become the first of the big four supermarkets to pledge a price match guarantee against discounters Aldi and Lidl in the latest episode of the ferocious price war.
The supermarket will launch a new loyalty card which will see ustomers given additional points if their comparable shop would have been cheaper elsewhere.
It is part of a previously-announced plan to invest £1 billion in price cuts over three years as chief executive Dalton Philips battles sliding sales and plunging profits.
Archbishop of Canterbury Justin Welby has welcomed Wonga's decision to write off the debts of 330,000 customers whose loans would not have been made under new affordability criteria.
He said the move was an effort to put right some of the things that have gone wrong in the past and the finance industry should be "a good servant not a bad master". But the head of the Anglican Church said the major issue was to create a reformed financial system.
"The big issue is to create a financial system that gives access to the poor and hope for the poorest in our lands, to be able to flourish and develop and have proper access to finance, not just for loans but for savings. For lives in which finance is a good servant, not a bad master."
If Wonga had found breaches in its lending process and taken the initiative in putting things right, they would deserve praise.
The truth seems to be different - behind the great "payday payback" is the Financial Conduct Authority, a powerful watchdog.
The FCA has new powers to regulate the payday sector and what we are seeing today is just the start.
Insiders at the Authority tell me - and I think they are correct - that many lenders are likely to simply leave the market between now and January - either because they cannot or will not apply new rules on checking customers ability to repay.
Wonga will contact all its customers by the end of next week to inform them if they will be among the 375,000 to be included in the redress programme announced today.
ITV News Consumer Editor Chris Choi reports:
Wonga to make changes to its affordability criteria and cancel the debts of those affected by inadequate checks
Wonga will be contacting all customers by 10 October to notify them if they will be included in the payback
Pay-day lender Wonga will write off £220 million owed to it, but the company will only feel the loss of £35 million as the rest is interest on the debts of the 330,000 customers.
Wonga has agreed to write off debts of 330,000 customers who are in arrears of more than 30 days. Move follows review of customer base.
New Chairman of Wonga admits it has been lending money to people who could not afford to repay it. Writing off debts of 330,000 customers.
Wonga Chairman, Andy Haste, promises "real and urgent" change. Henceforth will accept "significantly fewer loan applications".
Wonga is writing off £220 million owed to it but final loss to company only £35 million. Tells you something about interest it charged.
Wonga's new chairman has admitted the company made loans to people who could not afford to repay.
The statement comes after the payday lender's agreed with the financial watchdog to make significant and immediate changes to its business.
Debts for 330,000 customers currently in arrears of more than 30 days will have their loans written off, while 45,000 who are up to 29 days in arrears will be asked to repay without interest and charges over an extended period of four months.
Chairman Andy Haste said: "We want to ensure we only lend to those who can reasonably afford the loan in question and during my review, it became clear to me that this has unfortunately not always been the case.
"I agreed with the concerns expressed by the FCA and as a consequence of our discussions we have committed to taking these actions."
Wonga is to write off the debts of 330,000 customers whose loans would not have been made under new affordability criteria being introduced by the pay-day lender.
Virgin Money has confirmed it intends to list on the London Stock Exchange.
ITV News Business Editor Joel Hills is following developments.
Virgin Money (the bank formerly known as Northern Rock) confirms it's intention to list on London Stock Exchange.