What were the neutral Swiss doing with 265 German Enigma code machines during the Second World War? Find out at Glendining's sale of arms and armour, Thursday
Is there a secret hoard of German wartime Enigma code machines being systematically and profitably released on to the market? Yet another specimen is on offer at Glendining's sale of arms and armour, Thursday (2pm), with an estimate of pounds 6,000-pounds 8,000. The last one at auction sold for pounds 12,075 at Sotheby's in September. Hitherto, only one or two a year have appeared, fetching between pounds 6,820 and pounds 22,000.

This one is described as a "rare German" machine. German it certainly is, but it looks like one of a batch of 265 thought to have been bought by the Swiss from the German factory between 1939 and 1944 - many of which were sold off as army surplus as recently as 1991. Their identifying characteristics: four rotors instead of the standard three and lacking the wire-plug board of later models.

The sale of a military encoder to a non-ally during wartime is not as inconceivable as it might seem. Enigma was originally a commercial product, having been patented as a company-to-company secure communications device by the London Patent Office in 1927. A big batch of Enigmas for neutral Switzerland would have been a nice little earner.

Moreover, the German high command believed Enigma's enciphered signals to be uncrackable, even by machines in alien hands: the standard model, with three alphabetically lettered rotors, was capable of generating 17,576 codes, which, during battle, were changed daily.

Connoisseurs of militaria would profit by genning up on Enigma variations. How many models with wire-plug board were made and to whom were they issued? Was this model's remote, rather than built-in alphabet board used by Naval intelligence, as Glendining believes, or by Swiss anti-aircraft personnel watching for infringements of neutrality? Biggest mystery of all: of the 40,000 Enigmas made, how many survive?

Churchill's Sten gun, sadly de-activated, is at Christie's South Kensington's book and autograph sale, Friday (11am). He used to practice with it at Chartwell, after tea, still smoking his cigar. Est pounds 6,000-pounds 10,000. In the same sale, Oscar Wilde's inkstand - mightier than the gun? - est pounds 1,500- pounds 2,500.

At Bonhams, hub of contemporary ceramics sales: blockbusting Ries for up to and over pounds 5,000 and a unique 1976 Coper black cycladic form, less than 11in tall, for which pounds 18,000-pounds 25,000 is expected. Surprise lots: 12 pots by the Japanese Hamada from Jane Leach's collection: estimates - low hundreds to low thousands.

Novelty Victorian silver owl sugar casters, est from pounds 600-pounds 800, and other amusing trifles, at Phillips silver sale, Friday (11am).

Colourful Victorian Paisley shawls at Christie's South Kensington's costume and textile sale, Tuesday (2pm): estimates pounds 200 or so. An outrageously ornamental Saxe blue silk Aesthetic dress of 1882 is est pounds 500-pounds 600.

These days, the sale with the biggest crush: Clarice Cliff at Christie's South Kensington, Friday (10.30am).

For auctions nationwide, see pages 16 and 17

John Windsor