Marks & Spencer's UK like-for-like sales fell by 1.4% in the 13 weeks to 30 December, with clothing and home sales down 2.8% and food sales down 0.4%.
Total group sales fell by 0.1% to £3.2m. UK total sales were 1.1% higher but international sales plunged by 9.8%.
Steve Rowe, chief executive, said M&S had a mixed quarter with better Christmas trading in both businesses going some way to offset a weak clothing market in October and ongoing underperformance in food like-for-like sales.
Full year guidance remains unchanged.
The food business suffered from tighter budgets, while clothing and home was hit by an unseasonal October which meant it carried more stock into the December sale.
The fall in international revenue reflected the completion of the planned closure of owned stores in loss-making markets. In retained owned and franchise markets, constant currency revenue increased by 6.5%.
Rowe added: "We continue with the accelerated transformation programme we outlined in November and have recently taken several important steps to reshape the business for the future. These include a new technology partnership and organisation, and the sale of our Hong Kong based business in line with the streamlined franchise-led model we are adopting for International."