That is Coral spot. You need to prune out all and any stems with it on.

And do it immediately, don't wait, cut back to live, healthy wood. Remove any dead woody material from the area also, there's a risk it may harbour the organism which causes this. If you can, burn the infected wood, otherwise remove from the garden and dispose of it, preferably not in the garden recycling, if you have it.

Is this often seen on Pyracanthas ?
Does it appear on other shrubs ?

Ribes, Elaeagnus, Acers and Magnolias are particularly susceptible, TT, but it can occur on almost any woody plant. Starts on dead wood, spreads to live tissue and if left, may kill the whole plant.

Thanks, Bamboo ...
... sounds nasty ! :o(((

Fairly normal part of the decomposition process, but rather more aggressive than one would want on a living plant. I don't think that one in the picture is likely to be alive.

THANK YOU TO ALL WHO RESPONDED, I KNOW NOW WHAT I HAVE TO DO, AND WILL BE ABLE TO SPOT , IN THE FUTURE, IF I SEE IT AGAIN.

THANKS

LENNY

I had two Rowans that died from that. They died from the top down :(