Frost damage. Early morning frost and then the sun has hit this part of the laurel.

I have seen Aucuba japonica shake off a far deeper freeze than anywhere in the UK has seen this year, so I do not think it is frost damage.

It looks like it is getting too much sun and lack of water. I have noticed that Aucuba japonica can take months to show signs of stress, so you are looking at the effects nowish. The yellow leaves are also a sign of too much sun. They go deep green in deep damp shade with white spots.

The plant looks fairly established to me so water issues and sun shouldn't be a problem. I'd personally look at some sort of disease, maybe a kind of "wilt"....the green part of the plant looks like it's had it too.

I'd look if you can at the base of the plant/root area and soil

see if the base is healthy .....try the scratch test, if its not green then I'd look at the roots, maybe wrong but vine weevil come to mind :0 (

the leaves look rather small for Aucuba japonica, but two things spring to mind for me - possible weedkiller damage (have you sprayed anything nearby?) and the other, more likely and worse option, phytophthera infection, possibly at the roots, although there are several forms of this pathogen, some of which attack through the upper parts of the plant.

How many shrubs are there in the pictures. My 'frost' suggestion was based on there only being one shrub which had been damaged on one side only. Looking at the pictures again, could there be a row of them and just one of them is dying.

I thought weed killer damages myself, hopefully so rather than Bamboo's alternative suggestion.

If as Bamboo has suggested, you haven't sprayed nearby with a selective weed killer, then his other diagnosis of phytophthera would be my answer. The Aucuba is particularly susceptible and the leaves will eventually turn black and this can occur even on the most mature plants. No known remedy as far as I know, just cut back diseased stems to a clean bud and give a good feed in the spring.

Weedkiller spray would explain the die back. I have seen Vine weevil really attack Aucuba, so that is equally valid though easily investigated by giving the shrub a tug and see if there is much root left.