In reply to Joint:
I've flown with quickdraws quite a lot (in fact a whole rack in my hand luggage), and never had a problem. On a couple of occasions I've realised I left a nut key in there too, and that *definitely* looks like a weapon, but it's gone through fine. If you're off for a bit of sport climbing on a low-cost airline then I'd say most of the airports involved are used to it.
The only time I've had anything confiscated was a small cycling multi-tool: a set of allan keys. I guess they thought I might unscrew the aircraft one bit at a time, starting with the meal tray. The guy at security said that there's a restriction on carrying 'tools', and I know we're not supposed to try to argue about it, but I patiently explained that I hadn't seen any such restriction in all the literature about allan keys, and it's true, there's no restriction on things that are simply classified as 'tools' - they have different advice for different tools.
The most up-to-date list of baggage restrictions from gov.uk is here:
https://www.gov.uk/hand-luggage-restrictions
Under 'sporting equipment' there's no mention of anything particularly related to climbing protection.
But yeah, in the end it's partly at the discretion of the particular security guy, and arguing isn't going to help your case. If something's detected that they don't want you carrying through, most (UK) security zones permit you to either check the item in as hold-luggage (for a fee), or, if it's small enough, to post it to an address, so I guess if you're super concerned you could carry a large SAE or jiffybag so you can post 'em back. You'd have to make sure you'd allowed time before the flight to be able to do it though.
Post edited at 16:04