It looks like rose canker to me, which is a fungus. It's not that common in the UK but if it is that then your bush will eventually die if not treated. It can affect neighbouring bushes as well.

Cut out the infected parts straight away (and burn them). Prune back to an outward facing bud. Mulch with well-rotted manure and spray with fungicide. Feed in Spring.

If the disease persists then you may have to resign yourself to digging up the rose - and don't replant roses in that area.

No, it's not rose canker - I've been looking at pictures and it's nothing like.

If you look closely, there is a series of raised bumps along the stem just below a bud. None of the rest of the plant is affected. It causes the flowers to droop over, which seems to be a symptom.

It looks as if something's got into the stem and burrowed along and laid eggs or something - I don't recognise it, Sid. Cut one stem and slice through the middle, see what you can see inside...

Following this as its interesting to see what it is? Rose stem borer? My interest is because 2 of my roses have wilt and I can see no reason?

If this was an Ash tree, I'd be suspecting Chalaria fraxinus, or Ash dieback, but obviously, its a rose. I haven't seen that sort of patterning with canker before... but I'm wondering if anything visible is inside the blackened parts

The knobbly scar is rose sawfly see http://www.rhs.org.uk/advice/profile?PID=196.

The damaged areas need cutting out and burning before the eggs hatch. And the rose needs some tlc to get it back to full health.

Use an organic pesticide if you wish - please do not use Provado or any other insecticide containing thiacloprid (really annoyed that the RHS are still advising it's use!)

Goodness just seen it on the RHS Large sawfly page. As I have never seen it I wonder how common is this in the UK?

For distribution see the map on http://www.naturespot.org.uk/species/large-rose-sawfly. Looks like it's on the march as they're asking for sightings to be reported.

Big pat on the back for Urbanite - just been looking at the RHS pictures and the damage does look very similar. Think I've missed the boat for cutting the damaged parts off before the eggs hatch - you can see some tiny catapillars in my pictures. I must say, the words "saw-like egg-laying organs" kinda sent a chill down my spine! lol

Squish the caterpillars - still worth cutting out damaged parts as they are open doors for disease.

Some of the things in the insect world wouldn't be out of place in a horror film.