Not sure what that is, but it's not a Verbena!

Maybe a Viburnum?

Hard to tell what it is - the pic's sideways on and not close enough to see any leaf detail. Knowing what it is might give a clue to what the problem could be...

Oops,sorry meant to say Viburnum!

If this were where I live, I would suspect Texas root rot--not likely in the UK! Do Viburnums get honey fungus?

I'm not convinced its any kind of Viburnum, the leaves don't look right - looks much more like an Osmanthus or Elaeagnus, hard to be sure because of its current condition. I can certainly see what looks like a scale infestation on the twigs, right hand side, near the bottom, but unless its completely covered in scale, that wouldn't explain the condition its currently in. Its certainly possible its got one of the phytopthera infections, maybe at the root. And yes, Tug, they can get honey fungus - but we can't tell whether there's any rotting stump anywhere nearby. If its honey fungus, the toadstools should be visible in the vicinity this month.

Otherwise Huffmalling, suggest you inspect the whole plant from the bottom up, every twig and branch - you're looking for soft spots, weeping, missing bark, anything you can see that shouldn't be there and in particular, check the base of the plant, the 'trunk' if you like.

The foliage looks very much like Viburnum tinus, to me, though an Osmanthus is also a possibility. As Bamboo says, a close inspection of the lower "trunk" is definitely in order.