I'd say it was a Cypress of some type and if not cut back will become massive!. The brown bits at the bottom will probably not resprout green if you cut them out though.
It looks to me like, Chamaecyparis lawsonia 'Elwoodii.
Possibly suffering from conifer aphid or maybe salt spashing up from the patio.
Did you put any rock salt down during the winter ?.
Whatever the case, it's unlikely to grow back from hard pruning but may respond to shearing lightly on the affected foliage.
whatever it is, it's a conifer which has turned into a bush - I fear that if you cut into it to reduce it, all you'll be left with for some time is ugly bare brown branches from the inside.
Hi boxtops, there are many species of conifers and they take on many different habbits of growth. I have some at home that are 15 years old and no bigger than 8" tall. Some are long and tall, some are round, some are flat. It hasn't "turned" into a bush but was destined to grow that way since it was started as a cutting. Agreed that conifers hate being pruned.
Thanks everyone for your informative answers. The cutting back question has been settled by my OH who has made it quite clear that I am to leave it well alone. So our Chamaecyparis will continue to grow.