Sainsbury's festive sales boosted by Argos Black Friday surge

Sainsbury's saw sales inch higher over the Christmas period while receiving a Black Friday boost from its recently-acquired Argos brand.

Britain's second biggest supermarket reported a 0.1% increase in like-for-like sales for the 15 weeks to 7 January, while sales of wearable tech and mobile phones helped Argos to 4% growth.

Shares rose 6%.

The performance of the supermarket, which excludes fuel sales, was better than expected but paled in comparison to the 2.9% uptick posted a day earlier by rival Morrisons - its best in seven years.

Meanwhile, Lidl reported 10% growth over December though like discount rival Aldi - which said it saw total sales grow 15% in December - it did not publish like-for-like comparisons which would strip out the effect of rapid store expansion over the last year.

Lidl pointed to strong sales of prosecco and cut-price lobster.

Industry data suggests supermarkets have been enjoying their strongest growth for more than two years.

Sainsbury's overall group sales performance was lifted by strong Black Friday and Christmas trading from Argos - the brand it bought for £1.4bn in 2016, taking like-for-like growth to 1%.

But it warned that the slump in the pound since the Brexit vote - which has pushed import costs up and seen prices across the sector start to rise - and a tough market would continue to present a challenge.

Chief executive Mike Coupe said: "The market remains very competitive and the impact of the devaluation of sterling remains uncertain.

"However, we are well placed to navigate the external environment and remain focused on delivering our strategy."

Sainsbury's said it had a record Christmas week, with more than 30 million transactions at Sainsbury's and sales of over £1bn across the group, including strong growth for its supermarket online sales and convenience stores.

Industry figures this week showed supermarket prices were starting to rise again, but that follows more than two years of decline.

Sainsbury's said its customers paid 14% less for a basket of Christmas goods than they did in 2014, claiming its turkeys offered the best value on the market per weight.

But some chose to pay more for premium products, with sales of its Taste the Difference party food range up 50% year-on-year.

The group said Argos delivered strong growth with top sellers including Fitbit wristbands, iPad Mini tablets and Playstation 4 consoles.

It said the brand had a strong online performance over the Black Friday period, with 65% of sales taken via the web.