Morrisons Chief Executive Dalton Philips said it was investing £1 billion over the next three years in an aggressive price-cutting strategy to take on discounters such as Aldi and Lidl, saying:
We are going to lower our prices on a permanent basis.
The biggest challenge that we face is that there has been a fundamental change in how consumers view discounters.
They are no longer going to them out of necessity. The perception has changed and there is a new price norm.
The rules have changed and we must change too. It is absolutely critical that we begin winning again in our core supermarkets. To do that we must compete on price.
Mr Philips said that after 2015/16 no new supermarkets would be built other than in exceptional circumstances though its network of convenience stores would continue to be developed.
More top news
Police said the arrest showed how the matter was being taken "extremely seriously".
Windy with a soaking and limited winter sunshine
Mr Johnson said the checks would not be on goods travelling into Britain from the six counties.