The notorious London-based art critic Brian Sewell has recently gone on record as suggesting that art auctions give very rich men a chance to tell their rivals ‘my cock is bigger than yours’. Everyone who knows Mr Sewell will agree that he has always been fascinated with the size of gentlemen’s genitalia, notwithstanding the incredible prices being realised in the current round of London sales.

As the dust begins to settle on last week’s Giacometti jamboree, it’s time for the Contemporary auctions to take their stand, and it seems that this week ‘it’s all about Klein’. The great Parisian avant-gardist of the post-war post-modern era has increasingly become the doyen of the Contemporary scene, posing as he does as the ultimate ‘classic contemporary’.

With no exclusive gallery holding back work from the market and a very small pool of non-posthumous works to pick from, Yves Klein has quickly outpaced his colleagues Fontana, Manzoni, etc and become the ‘hero of Zero’ (as I overheard one over-zealous Sotheby’s executive exclaim in the viewing room today). Certainly, there are some stellar works on offer this week, seemingly flushed out of European collections due to the rapid rise in the artist’s prices (in particular see results at Sotheby’s New York in 2008).

Sotheby’s opens up with three works offered from the Sammlung Lenz Schonberg in their evening sale on Wednesday, most notably a vast fire work, titled F88, estimated at £2.8-£3.5 million. I fully expect this piece to fly, likewise the gold leaf panel MG 25 (£800-£1.2 million) and the more typical blue pigment on canvas IKB 45 (a snip at only £500-£700,000). But the star of the week really has to be RE 47 II at Christies, selling in their evening sale on Thursday. One of only two sponge reliefs to have been produced in gold, it represents the epitome of the artist’s output and must surely fly into 8 figure territory (against an estimated £5-£7 million). The cover lot was reserved for another Klein, a blue spray work Anthropometrie (ANT 5), offered at £1.5-2million and arguably the best example of its kind.

Whatever the outcome, whoever holds the other gold sponge relief is likely to have an interesting week ahead of them!