Ananova:

The fiercest Christmas supermarket price war in a decade looks set to break out across Britain as the nation's four biggest chains reveal their festive offers.

Asda has declared that it is cutting up to £150m off the cost of Christmas products in a bid to entice shoppers looking to stuff their families' stockings.

It is promising that this year will be its most aggressive on price in 10 years, as its parent company Wal-Mart announced the supermarket's like-for-like sales rose by 5.6% in the last three months - down from 7.2% in the previous three-month period.

Meanwhile, Asda's main rivals have all launched their own battles to draw in customers.

Sainsbury's is encouraging shoppers to make the best use of their Nectar loyalty card to cut the cost of their shopping, with an advertising campaign showing the value of collecting points.

It is also promoting a three-for-the-price-of-two offer on Christmas gifts.

Tesco hit back at Asda's offer with a £250 price cut pledge, which will include everything from a £6 turkey to a half-price BMX bike.

It has also chosen to push its loyalty scheme, with a double-Clubcard-points-on-all-purchases promotion.

And Morrisons has re-launched its collector card that gives shoppers who spend £40 or more in one transaction each week for five out of six weeks between November 9 and December 20 a voucher for £25 off their Christmas week shop.

"It is important for their brands for the supermarkets to be seen to be helping hard-pressed families at this time," said Sky News City editor Mark Kleinman.

"The big four supermarkets have already stepped into the void left by the demise of Woolworths and Zavvi.

"This is the first time for many years that all of the big four - Asda, Tesco, Sainsbury's and Morrisons - are really firing on all cylinders.

"It will result in a price war that will be interesting for the City to watch."

The Christmas competition is set to benefit shoppers who have been hit by rising food prices throughout the recession.