The UK's fifth-largest supermarket chain said sales in December rose by 0.4% compared to the previous year, when grocery spending was higher than usual due to the national lockdown and temporary closure of bars and restaurants.

It claimed the return of its character Kevin the Carrot in festive Christmas TV commercials helped it win customers at the expense of rivals but, as is usual for Aldi, it offered no like-for-like data on how existing stores had performed based on the same period last year.

Without it, market analysts can only speculate on whether the growth came purely from new store openings and one declared that the festive season had clearly been disappointing for Aldi.

Mindful of the inflation problem, Aldi said it committed "to offering shoppers the lowest grocery prices throughout 2022".

The company released its update after industry data last week showed that Aldi and its main discount rival Lidl had enjoyed the strongest rates of sales growth over the festive season.

Kantar Worldpanel said that while sales at both were more than 16% higher over the 12 weeks to 31 December, Tesco had won the race for greater spoils among the 'big four' players which include Sainsbury's, Morrisons and Asda.

The rush to the discounters at Christmas piles pressure on the more established chains as shoppers face a squeeze on their budgets due to surging inflation.

Kantar reported that grocery price inflation was 3.7% over the festive season.

The wider headline rate, the consumer prices index, is already at its highest level for a decade - led mostly higher by rising wholesale gas costs within energy bills.

They are tipped to rise more dramatically in April when the next adjustment to the price cap is introduced.

The industry has warned that, without government intervention, the average annual bill for heating homes could hit £2,000.

It currently stands at £1,277.

Since the financial crisis, supermarket chains have largely been locked in a price war in a bid to protect their market shares.

Aldi, the Kantar figures showed, was just over two percentage points off Morrisons.

It is continuing its rapid expansion, revealing in September that it planned to create 2,000 jobs this year and grow its store base by 100.

It will give Aldi more than 1,000 UK stores when completed.

Giles Hurley, Aldi UK's chief executive, said: "As we look ahead, the top priority for most families this year will be managing their household budgets in the face of rising living costs.

"As the cheapest supermarket in Britain, Aldi will always offer the lowest prices for groceries, no matter what, and continue to support our British farmers and producers."

Kunaal Shah, associate retail analyst at GlobalData, said the company was putting a positive spin on a poor festive season.

"Aldi's December sales inched up on a strong 2020 but considering its aggressive store opening program, its Christmas performance was disappointing and like-for-like growth will be in negative territory."