Anyone know what this shrub is?

[cloudtree]

In the garden at the natural history museum

Maybe a Lycianthes rantonnetii or some related solanum?

The Picture This app says Kangaroo Apple.

It's a great app.

Yeah agree with kangaroo apple. It was collected by/brought to the UK by Joseph Banks, a lot of the garden design is based on what scientists/plant collectors have brought to the NHM collections (and its previous names/owners) over the centuries. You should be able to find some Banksia species but I haven't been in a few years so they might have died 😅