Tesco has reported a marked slowdown in UK sales growth for its first quarter, with comparable sales rising 1.8% in the three months to the end of May, well below the 4.2% recorded in the previous quarter and short of the 2.3% analysts had forecast. The retailer pointed to a poor spring, easing grocery inflation, and consumer unease over the Middle East conflict as the principal factors behind the weaker performance.

Ken Murphy, chief executive, was direct in identifying the cause. He said that the rainy weather that prevailed for a large portion of this spring had a greater impact on supermarket expenditure than any other factor, including the World Cup. Sunshine, in his assessment, prompts households to eat together more frequently, entertain and spend more. This spring offered little of it. The year-over-year comparison is unfavourable because the same time last year had a prolonged spell of mild weather.

England's opening fixture against Croatia on Wednesday produced a 40% surge in sales through Tesco's Whoosh rapid delivery service. Scotland's win over Haiti on Sunday drove even sharper increases, with Irn-Bru volumes up 50% and canned cocktails rising 185% in the hours before kick-off. Murphy welcomed the results and said strong home nation performances would give the country a lift, but he did not revise his view that football's influence on the overall market is secondary to the weather.

Comparable UK sales reached £13.4bn over the quarter. Group revenues rose 1% to £16.8bn, with online sales providing the clearest point of growth, up 8.9%. The wholesale division, Booker, went in a different direction. Sales there fell 3.2%, with revenues from independent retailers and catering businesses both declining amid difficult conditions on the high street.

Murphy acknowledged that consumer confidence remains subdued. The ongoing conflict in the Middle East has pushed petrol prices higher and raised concerns about household energy costs later in the year. He said these pressures had not yet translated into meaningful changes in how customers shop, but the uncertainty is a feature of the current trading environment rather than background noise.

On grocery inflation, Murphy said the picture had improved. In order to protect themselves from rising energy costs, food producers acted faster than anticipated, and commodity prices for coffee and cocoa have dropped from recent highs. He does not expect inflation to reach the 9% level some industry bodies have projected. Petrol pump prices, he added, were already falling as diplomatic progress between the United States and Iran created cautious optimism around energy markets.

Tesco said it had extended its price-matching commitment against Aldi to more than 2,000 of its smaller Express stores and introduced 520 new product lines during the period. The company reaffirmed that it expects to meet full-year profit guidance, with analysts forecasting £3.25bn for the financial year. That would follow an 8.5% rise in annual profits to £2.4bn reported for the year to 28 February, when group sales grew 4.3% to £66.6bn.

Despite the guidance reaffirmation, shares fell 2.4% in early trading. Tesco holds its annual shareholder meeting later today.