Outer Defences Tour

Fort Nelson is running an Outer Defences Tour on Saturday 20 March, and it's one of those rare chances to see the place from the outside in. Most of us know the fort for what's inside the walls, but this one takes you beyond them and down into the vast ditch that served as the fortress's first line of defence. You'll find out how that ditch was carved out and the role it played in keeping the fort secure, alongside the defensive features built into the interior.

It's a bit of a perspective shift. Instead of looking out from the ramparts, you're standing in the very gap designed to stop an approach. You'll get a sense of the engineering, the labour, and the ingenuity that went into making Fort Nelson such a formidable stronghold, and you'll leave with a much better handle on how the whole thing actually worked as a defensive system.

For context, the fort itself is a restored Victorian fortress on Portsdown Hill, overlooking Portsmouth Harbour. It covers more than 19 acres of tunnels, ramparts, and artillery gathered from around the world. Among the collection is a 15th-century Turkish bombard cannon, a 200-tonne railway howitzer, and the infamous 'Big Babylon' Iraqi supergun.

There are two tours on the day, one at 10:30am and another at 2pm, each running for 90 minutes. Tickets are £12. A few practical things to keep in mind: the tour is conducted entirely outdoors, it's not accessible, and it involves uneven ground and steep slopes, so sturdy footwear is a must. If you're planning to go, the fort is at PO17 6AN.