Discount grocery chain Aldi is now the UK's sixth largest grocer, overtaking Waitrose, a survey has found.
In the 12 weeks to 29 March, Aldi had a 5.3% share of the grocery market, according to research firm Kantar Worldpanel.
This pushed it ahead of Waitrose, which had a 5.1% share.
The UK's largest supermarket chain, Tesco, clawed back some ground. Sales in the 12-week period rose 0.3%, giving Tesco a market share of 28.4%.
In recent years, the big four UK supermarket chains - Tesco, Asda, Sainsbury's and Morrisons - have come under increasing pressure from the discount chains.
Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, said: "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."