Primary radar systems at British airports.
It's been a few years since this was discussed.
At Leeds Bradford the 1989-vintage Plessey Watchman is still turning and doing the business. I believe its had a few upgrades and tweaks over the years, some very recent. As far as I know, none of the NATS airfields are still using the Watchman but I think Newcastle and East Midlands still have their Marconi S511s. Built to last ?