Waitrose led the promotional activity in the UK grocery sector last month, according to the latest data from the just-food Promo Tracker.

Four out of the six retailers monitored by the Tracker - Waitrose, Ocado, Tesco and Asda - had a lower percentage of their SKUs on offer in June than in May, the figures showed.

However, the Tracker, compiled exclusively for just-food by mysupermarket-insights.co.uk, showed the biggest month-on-month increase was at Waitrose. In May, 28.3% of its SKUs were on promotion; in June, that went up to 33.15%.

The average saving per promotion increased at Tesco, Sainsbury's and Waitrose, although at Asda, Ocado and Morrisons it fell when compared to the levels the Tracker reported for May.

Chilled desserts broke into the top five most-promoted categories.

German food group Dr Oetker's Onken and Kraft Foods' Green & Black's moved into the top ten most-promoted brands in June.

Supermarket Total number of SKUs Number of Promos % of all SKUs on promo Average saving per promo
Tesco 35258 14316 40.6 £1.07
ASDA 29183 6699 22.96 £0.44
Sainsbury's 25219 8809 34.93 £1.13
Ocado 21217 8524 40.18 £1.39
Waitrose 22602 7493 33.15 £1.16
Morrison 11522 4783 41.51 £0.45
Category PcntOfPromos AvgSavingPerPromo
Yogurt & Milk Drinks 65.6 £0.48
Yogurts 62.6 £0.31
Crisps 56.52 £0.59
Chilled Desserts 53.23 £0.35
Baby Food & Snacks 52.61 £0.23
Frozen Pizza & Breads 51.61 £0.57
Snack Meals 51.52 £0.26
Frozen Vegetarian 50.66 £0.42
Cooked, Prepared Meat & Poultry 49.85 £0.71
Fresh Herbs 45.86 £0.27
Ice Cream 45.47 £0.9
Sausages & Burgers 42.74 £0.55
Pasta Sauce 42.16 £0.5
Fresh Vegetarian Food 41.27 £0.6
Tinned Pasta 40.29 £0.23
Desserts 39.65 £0.21
Frozen Ready Meals 39.23 £0.51
Fruit 39.03 £0.72
Fresh Pasta & Pasta Sauce 38.23 £0.41
Fresh Pizza & Chilled Bread 38.17 £0.68
Brand PcntOfPromos AvgSavingPerPromo
Actimel 96.8 £0.67
Innocent 93.5 £0.54
Muller 90.3 £0.36
Benecol 86.2 £0.54
Activia 86 £0.21
Onken 81.7 £0.17
Tilda 78.3 £0.62
Slim-Fast 77.6 £0.76
Green & Black's 76.5 £0.75
Tesco Italian 76.4 £0.4
Rachel's 75.7 £0.27
Häagen-Dazs 73.3 £0.92
Snack-a-Jacks 72.6 £0.33
Batchelors 72.5 £0.18
Walkers (Crisps, Snacks & Dips) 71.8 £0.49
KP 70.6 £0.55
Pringles 68.2 £0.95
Tyrrells 66.7 £0.63
Yeo Valley 65.7 £0.36
Homepride 65 £0.28