The strange looking contraption you can see in the photo is a salmon fish trap used on the River Severn during the 1950s. I was rather surprised to find a couple of metal ones on display as I've only seen ones woven from willow before. You can see the more traditional structure and an explanation of the fishing here. I felt rather sad to see them as it probably means someone has stopped fishing the Severn in the traditional way: it's a technique that's dying out as and when the fishermen retire. However, looking on the bright side using them for a different purpose is far better than just throwing them away.
I'd love to have one as a companion for the woven one I have in my study as I write this. A friend brought it back as a gift from her trip to Cameroon to remind me of my fishy past when I researched salmon and trout populations. That was here in the UK rather than in Cameroon, but I did appreciate her thoughtfulness. However, the price of the salmon trap on display is a bit too steep for me. Mark managed to acquire some for Otter Farm recently, so I'm hopeful I might find a cheaper source soon. I won't be using it for the purpose suggested on the label you can just see in the picture though: it's for growing sweat peas ;)