I spotted one on 1st July at fairburn
Highly unlikely, Andrew. They're not an urban bird. I suspect it was a young robin you saw, though obviously that's a guess. Female redstarts can be confused with nightingales, but not likely in Leeds.
Andy's photo is a warbler. Hard from that angle to be definitive, but has all the makings of a chiffchaff.
From its appearance I thought it was a Chiffchaff or a Warbler of some kind, and used my Ornidroid app to try get an ID on it, but none of them matched it's song.
I asked a twitcher that was there and he couldn't ID it as he'd never heard the song before.
I searched the net for it to match its song, and found it was a Nightingale.
My first paragraph was to Andrew (though I appreciate Andy and Andrew can be confused). His sighting was Leeds which is urban.
The photos on your gallery, Andy, look like song thrush.
Re Fairburn sighting, it isn't a nightingale, sorry. Nightingales typically sing til early June approx. Although an unusual angle, the photo clearly shows it isn't a nightingale. Bill is wrong as well as overall appearance and primary projection.
I certainly couldn't guarantee is as a chiffchaff (although photo alone it would be hard to prove otherwise). If that was the bird heard singing, and it didn't sound like a chiffchaff, but more melodic, then I am not sure what to suggest warbler wise.
Did you get another photo, or a recording of the song, Andy?
Thanks for the Id I appreciate it, however I'd be wary of sweeping statements saying leeds is urban is a little misleading it's a vast city and this shot was taken in Temple Newsham approximately 1500 acres of woodland and parkland