When I was checking out other possible stockists for the wines I picked out from the recent Sainsbury’s tasting here and here I was shocked to find how much more they were charging for some of their top end wines than their independent competitors.

Sarget de Gruaud-Larose Saint Julien 2002 for example is listed at £22.99 yet on wine-searcher.com I found two independents which were charging £10 and £13.62 a bottle and one which was charging £16.01. Berry Bros & Rudd is charging £16.98 for the 2005 so where has Sainsbury’s plucked their figure from?

And we're not just talking Bordeaux. The 2004 vintage of Penfolds Bin 389 - £18.99 in Sainsbury’s - I found at between £13.18 and £14.81 in two independent wine merchants.

There are significant mark-ups on champagne and white wine too. The 1999 vintage of Laurent Perrier Millésimé is £39.99 in Sainsbury’s - and £34.03 at Oddbins with a further 20% off if you buy six bottles. In Jeroboams you can buy a bottle of Chanson Chassagne Montrachet 2006 for £25.96. In the 139 branches of Sainsbury’s that stock it you’ll pay £29.99

Of course you could argue, and Sainsbury’s no doubt would, that many of their customers would like the convenience of buying a single bottle of an expensive wine rather than a case - mixed or unmixed - and that not everyone is fortunate to have a merchant on their doorstep who will sell them a single bottle. All true yet I’m sure they wouldn’t be too pleased to discover how much over the going rate they were paying for them. Especially as Sainsbury's must be able to negotiate a much better deal than a tiny independent.

Call me a cynic but I smell a Christmas promotion in the offing where Sainsbury’s miraculously reduces the cost of these wines by 50%. Only you and I will know the actual reduction is much less.