Well, it might survive, but it's only going to get wider. It will never grow upwards from that pruned top. If it were me, I would be removing it.

My neighbours

Gods waiting room though it may live on for years.

Depends on whether there are buds lower down the dead looking branches.

Looks like a thuja hedge, these are one of the conifers that respond well to drastic pruning, that said when a thuja hedge has been renovated like yours then sometimes the middle will not recover, but I don’t think this hedge is ready for heavens waiting room, in my experience you need to let it grow up a little, soon the top sides will be over the middle bit then once slightly trimmed over time it will completely hide the mid section, let me give you an example, over in France, where one side of a thuja hedge had to be cut right back to keep the mare happy, I topped it slightly and cut all the roadside back yes it looked unsightly, I explained the situation to the lady and she understood, it responded very slowly but here’s the secret you don’t touch the back of the hedge and all the long growth is poked through and trimmed carefully, it now is a compete hedge that you would not know had been renovated, yes it took a few years but that’s gardening for you, patience is the key and going back to yours it looks like it has many years left so long as you nurture it.

Well spotted Julien. I hadn’t recognised it as Thuja.it looks just like lleylandii to me. Apologies.

I would reduce the width by 2/3. If that doesn't work then it's time for an updoo.

On this little laptop I thought leylandii too so we are in good company together Karen.

Wow Julien, that's so clever!

So Julian it's like a comb over!