Shares in Tesco and Sainsbury's tracked the FTSE 100 higher on Monday, despite fresh evidence that Lidl is taking market share.
Lidl GB, the British arm of Germany's Schwarz Group, grew revenues 10.8% to about £13 billion in the year to February 2026.
Shore Capital, the broker, estimates like-for-like volume growth of about 5%, though it admits that figure is a guess.
It reckons like-for-like volumes at rival discounter Aldi fell by 4% to 5% over the same period.
Lidl plans about 50 new stores in its current financial year, up from 40, backed by roughly £600 million of UK investment.
Its market share is close to 9%, against about 10% for Aldi, according to Shore's reading of NIQ data.
Lidl Plus, its loyalty scheme, grew participants by 23%.
Tesco, the UK's biggest supermarket group, reports half-year results on Thursday.
