The supermarket chain will be selling petrol at no more than 99.9p per litre and cutting diesel by 1p a litre, reports The BBC.
The price of crude oil continues to fall, with Brent now below $40 (£26.38) a barrel – close to a seven-year low.
Other supermarkets are expected to follow Morrisons. Asda is running a weekend 99.7p promotion on petrol.
From Friday until Sunday only, drivers at Asda will pay that price for petrol and 103.7p a litre for diesel.
Morrisons’ petrol retail director Bryan Burger said: “Today, for the first time in more than six years, we are moving unleaded prices down to below £1 a litre.
“This is a moment where motorists will feel some relief after being clobbered by tax and price rises for the last decade.”
The company said it would hold the price “for as long as possible” but that it remained subject to changes in the oil and currency markets.
When the price of Brent crude fell below $40 a barrel earlier this week, the RAC predicted that petrol and diesel prices would fall below a pound a litre at supermarkets before Christmas.
Morrisons new price is just a whisker under that mark, but symbolic nevertheless.
It’s a pre-emptive strike against its main rivals to drive footfall in the all-important Christmas trading season, and to bolster its battle to win back customers from the discounters.
The other big three supermarkets will likely follow suit, but it may still be some time before the average price of unleaded petrol reaches the £1-a-litre mark.
