Bunting, Pimms and even Jubilee gnomes are flying off the shelves as retailers and consumers ready themselves for "the party of the year".
Supermarkets expect the four-day break to be one of the busiest weekends of the year with customers remaining in the UK for street parties and family get-togethers.
Waitrose said sales of Pimms - considered by some in the sector to be a "litmus paper for the feel good factor" - were up by more than 260% on last year, with the spirit outselling every other in the range.
The retailer said cider was proving a patriotic favourite with sales up 70% on last year, while trifle was up 28% and picnic or party paperware up 182%.
Asda is also predicting a 75% increase in sales of Pimms, and has 2.8 million Victoria sponges and one million cucumbers in stock for the weekend.
DIY retailer B&Q said it had sold 100,000 metres of Union Jack bunting, 10,500 Jubilee cushions and 3,100 Jubilee gnomes.
Sainsbury's reported sales of 364 miles of bunting and 146,000 flags, with Union Jack cake stands up 2,783% and Union Jack teacups and saucers up 5,588% week on week.
It also expected to sell nearly 10 million servings of strawberries, one million jars of jam, four million loaves of bread, 20 million cans or bottles of beer, 295,000 bottles of champagne and 180,000 bags of charcoal over the weekend.
Sainsbury's general merchandise director Robbie Feather said: "Record sales of flags and bunting were seen in 2011 thanks to the royal wedding but current indications show that the Queen's Diamond Jubilee is set to far outstrip last year's demand."
Tesco party range buyer Matt Compton said: "This is the biggest week we have had since the Millennium in terms of party sales with demand far exceeding sales last year's royal wedding, and we haven't even reached the weekend yet."