M&S said like-for-like sales fell 1.2% in its clothing and home division over the 13 weeks to July 1, against a 5.9% tumble in the previous three months.
Its food halls also saw a better quarter, with same-store food sales 0.1% lower.
M&S said this year’s later Easter boosted clothing and home sales by around 0.6%, while it helped lift food sales by around 0.7%.
Chief executive Steve Rowe also said efforts to cut-back on promotions as part of his overhaul plan helped full-price clothing and home sales jump 7% higher in its first quarter.
The group started its summer sale on Tuesday this week, with “significantly” less stock to discount.
Mr Rowe said: “Trading in the first quarter was in line with our expectations and we are on track with delivery of the plan we announced last year.
“I am pleased that we continue to grow full price sales in clothing & home, with reduced discounting and no clearance sale in the quarter.”
Mr Rowe said the mood among shoppers on the high street was “volatile”.
He said consumers are “very much shopping for now and cautious with their spend”.
The group has struggled to halt falling sales in its clothing and home division, but Mr Rowe said the absence of a clearance sale in the first quarter knocked around 2% off like-for-like figures.
M&S also axed 27 promotions in the quarter.
Mr Rowe said he hopes clothing and home sales will begin to turn positive towards the end of the year.
The group’s food sales were lower than expected and remained in the red despite surging inflation, which M&S said was running at around 2% in its first quarter.
Part of the fall came as it opened Simply Food stores near existing shops, which impacted some sales, while the group also cut back on promotions.
Total like-for-like sales across all departments were 0.5% lower, while it saw online sales rise 5.8% at M&S.com.
Overseas sales were 4% lower with currency changes stripped out as it shut 28 of 53 stores under a plan to pull out of 10 international markets to refocus on its core UK business.