DISCOUNT supermarket Aldi has overtaken upmarket rival Waitrose to become the sixth largest grocer in the country, industry figures showed today.

Aldi achieved a 5.3% market share in the 12 weeks to March 29 in the latest till roll figures from Kantar Worldpanel after boosting sales by 16.8% during the period.

This beats Waitrose, which had been the sixth largest grocer, which saw sales lift 2.9% to claim a 5.1% market share.

In a mixed bag for the big four supermarkets, Tesco continued to make gains under a turnaround by new boss Dave Lewis seeing sales grow 0.3% to give it a 28.4% share, while Sainsbury's lifted sales 0.2% to a 16.4% market share.

But Asda saw its sales fall 1.1% to give it a share of 17.1%, while sales at Morrisons fell 0.7% to a 10.9% market share.

Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, said: "Aldi has recorded double-digit sales growth for the past four years and is now Britain's sixth largest supermarket with 5.3% of the market."

He said Aldi's growth had been fuelled by over half a million new shoppers visiting Aldi this year, with its average basket size increasing by 7%. But he added that although the grocer's rise was high compared to rivals, it was still slower than in recent times.

The country's other large discount supermarket Lidl saw its sales jump 12.1% over the period to a 3.7% market share.

Mr McKevitt added: "The changing structure of Britain's supermarket landscape is illustrated by two facts.

"Firstly, the so called discounters Aldi and Lidl now command a combined 9% share of the market. In 2012 the same two retailers only accounted for 5.4% of grocery sales.

"Secondly, the 72.8% share taken by the biggest four retailers is now at the lowest level in a decade."

The report said that consumers continued to benefit from falling prices that were now 2% cheaper than a year ago.

The survey said pressure from discounters had led to prices falling across the industry for 19 months in a row as a result of higher levels of promotions and deflation in major categories such as vegetables, milk, eggs and bread.