Sainsbury's decision to buck the trend with bogofs appears to have led to a flurry of me-too activity among its rivals.

The mechanic accounted for a whopping 65% of Sainsbury's ­featured space promotions last weekend - even higher than the 30% reported in the year to date. Only four mechanics were captured in the multiple: bogof at 65%, x-for-y at 16%, save at 15% and half-price at 4%.

But despite bogofs having shown signs of declining in popularity in other multiples, last weekend Tesco, Morrisons and Somerfield all had bogof as their ­primary mechanic.

When looking at overall promotional activity last weekend, buy-one-get-one-free offers accounted for 33% of all offers (up from 19% in the first three months of the year), x-for-y 28%, save 24%, half-price 10%, extra-free 3% and special purchase 2%.

A total of 137 brands used the buy-one-get-one-free promotional mechanic last weekend, and of those 68 used it exclusively.

Morrisons used five mechanics last weekend - bogof at 38%, x-for-y at 27%, save at 23%, half-price at 7% and extra free at 5%.

Tesco's bogofs secured 30% of secondary space offers, with save used on 29% of promotions, half-price on 27%, x-for-y on 10% and special purchase on 4%.

Somerfield's activity was more even but again bogof led with 28%, x-for-y accounted for 26%, half-price and save were both at 20% and extra-free took the remaining 6% of offers.

Asda, which scrapped the bogof mechanic in favour of Every Day Low Pricing years ago, showed a huge bias towards x-for-y, with the mechanic accounting for 63% of offers last weekend. Save was used on 31%, special purchase on 5% and extra-free on 1%.

In terms of category activity, bogof was the preferred mechanic in six categories last weekend.

Meat, fish & poultry used the mechanic in 83% of its offers, chilled foods 66%, bakery 63%, health, beauty & baby 55%, chilled dairy 51% and impulse 38%.