Four items which claim to be related to the Dams Raid are coming up for auction this Saturday (1 July) by the Northamptonshire firm of J P Humbert. Two lots are being sold by the same collector who sold the wooden bomb sight used on the Dams Raid in January 2015. He had acquired the bomb sight from Hydneye House school when it closed in the late 1960s. The school had previously been owned and run by my grandfather Ettrick Maltby, father of Flt Lt David Maltby, pilot of AJ-J on the Dams Raid. Afterwards, David had given the bomb sight to his father.
When Ettrick Maltby retired in 1955, he handed over the bomb sight and two items of navigational equipment to the new headmaster, Gerald Brodribb. Brodribb kept the letter, seen below, and it was used at the 2015 auction to establish the provenance of the bomb sight and navigational equipment.

However, it now seems that the same collector has come across another artifact, a bomb release switch (see below), and is also putting this up for auction. However, there is no mention of this item in Ettrick Maltby’s letter and nor was it one of the substantial number of items shown to George “Johnny” Johnson when the collector met him in 2008 and asked him to authenticate them.

A standard Lancaster bomb release switch is shown here in a well-known wartime publicity photograph. It is claimed that the item for sale is a non-standard one which was removed from aircraft ED906, code letters AJ-J, after the Dams Raid and then given to Ettrick Maltby before David’s death in September 1943. However, in the summer of 1943, ED906 was still being used by 617 Squadron for test drops of the Upkeep weapon and therefore its bomb release switch should still have been in place.
IWM CH12283
I have only been able to examine the single photograph of the item being sold shown above, and would counsel any prospective purchaser to look at the original item, rather than a photograph. From the photograph, it would seem that it has different wiring from the standard release switch. A wire comes out on each side of the casing before being twisted together below. The standard bomb release has all its cabling gathered together in a single thicker cable which would have given it more protection when in use.
Furthermore, there is absolutely no evidence that the release switch on the Dams Raid aircraft was changed from the standard model. Indeed there would be no need for it to have been, although the fuzing mechanism was modified. Release of the Upkeep weapon was activated by a standard electro-mechanical bomb slip in the bomb bay roof and all that was required was to arrange the wiring circuit from this to the release switch, so that it was direct, by-passing the usual bomb selector panel options, which normally enabled the bomb aimer to select bomb stations in order to programme the sequence of release. Regardless of the circuit it could still have been activated by the standard release switch.
All RAF stores and equipment carried an “AM” [Air Ministry] stamp. The fact that this is apparently stamped in this fashion merely adds credence to the fact the item is a piece of Air Ministry equipment.
As is usual in auctions, everything is always sold “as seen” and with numerous caveats. However, if this item is a genuine modified Lancaster bomb release, then my advice to prospective purchasers would be to seek further provenance before the sale.
Three further lots are also being sold on Saturday. One is a group of four marbles which purport to be amongst those used by Barnes Wallis in his “bouncing bomb” tests. Again, these are not mentioned in the letter from Ettrick Maltby and there is no documentary evidence to connect them to the Wallis family.
The other two items come from a different vendor, a fitter who worked on the scrapping of Guy Gibson’s aircraft ED932 (AJ-G) in 1947, and appear to have been in his possession since. If the letter authorising their removal, which I have not seen, is genuine there is no reason to doubt their veracity.