Waitrose boss Mark Price has flagged that there will be an impact on first-half profits as “unprecedented investment” is made in the business.

Despite sales growth of 5.2%, excluding petrol, for the half, Price said profits will be impacted when it reveals its interims next month.

Price said: “In a more turbulent time for food retailing than any of us can remember we have outperformed the industry, won more customers, increased our market share.

“We are investing to enable us to compete effectively in this very tough market and to build a strong business for the future. That’s why we’re putting substantial investment into offering great value to our customers.”

As well as price-matching and more promotions, the grocer is giving loyalty card myWaitrose members deals on staples like butter and milk without cutting the price it pays to the British dairy farmers it sources from.

Price said it is also building its online business, opening new shops and improving existing ones, offering new services and hospitality, and using myWaitrose to understand its customers more. ​

He said: “Everything we’re doing is enabling us to compete well now - continuing our five-year out-performance of the industry - and build the modern Waitrose equipped to succeed in the very different grocery landscape of the future.”

Over the past week, Waitrose sales, excluding petrol, rose 6.7% to £121.9m.

'Unprecedented investment' to take toll on Waitrose first-half profits