Attracting birds to dingy back yard?

I have recently moved into a rental property near the Mersey estuary after living overseas for many years. There are lots of wonderful waders etc. if I go out for walks but the back yard is depressingly small, north-facing, closed in by other houses and completely ignored by birds. There are no trees or shrubs and so far I just have a few pots with small plants back there (and they're not exactly thriving). I'm desperate to have some birds visit but so far all I see is the occasional magpie on a nearby rooftop.

Any suggestions about things do to attract birds to this frankly unattractive spot?