Something in my flat on Holloway Road - possibly poltergeist activity?

This is probably going to sound mental, but I need to get it down somewhere before I convince myself I imagined it. I moved into a basement flat on Holloway Road in North London about eight weeks ago. It's cheap, obviously, because it's a basement, but I've been generally fine until about a week ago.

What's been happening: Doors opening that I distinctly remember closing. My kitchen tap turns on by itself - not constantly, but I've caught it three times now at odd times (2am, 4:30am, midday). Most recent thing: last night about 11pm, I heard what sounded like someone knocking on the radiator pipes. Three distinct knocks, then silence.

I'm not particularly imaginative or prone to panic, but I'm genuinely unsettled. The neighbours haven't complained about water issues. My boiler's been serviced. I've looked for logical explanations first. But I'd like to know if anyone else has experienced similar and whether it's worth calling in someone to have a look, or whether I'm just being paranoid about an old building.

Witnesses: My mate Dave was here for the tap incident on Friday and saw it turn on. Weather that week: dry, no temperature fluctuations.

Holloway Road is old London. Lots of old buildings with quirky plumbing and pipes. Water hammer in the pipes can sound like knocking, and old plumbing can cause taps to open if there's a valve issue. The door opening thing is more common than you'd think in older flats - uneven floors, air pressure from windows, etc. Have you got a carbon monoxide detector? Sometimes that's the first thing to check before assuming paranormal.

I heard what sounded like someone knocking on the radiator pipes. Three distinct knocks, then silence.

I lived in a basement flat in Islington (very similar to yours) and experienced almost exactly this. The tap thing freaked me out until an engineer explained that old isolation valves can be faulty and water pressure changes can trigger them. The door thing was literally just wind and air pressure. Sounds paranormal when you're in a basement and slightly on edge.

Not saying there's definitely nothing paranormal happening, but you're right to look for logical explanations first. Basements in old London buildings are inherently weird - cold, damp, creaky. That plays tricks on your mind even without actual activity. Get the plumbing checked, check for drafts, and monitor for two weeks. If it keeps happening after mechanical issues are ruled out, then consider calling someone in.

The knocking on radiator pipes thing is SO common in old London flats. My radiators do it all the time and it sounds distinctly like someone tapping. Once you know what it is, you can't unknow it, but it's genuinely just the pipes. Good call getting your mate to witness the tap thing though - that's proper investigative thinking.