Ooh that looks quite nasty. I think it looks like an abscess caused by an injury. The red part appears to be the birds own skin,very inflamed poor bird.
I'd wait for other opinions tho I'm no vet lol :))

I thought the same as Aster Janette.Looks very sore and angry. Hopefully it will burst in time..and the poor bird will have some relief.....

Thanks Aster and Jane for your help ,although it looks pretty awful .it has,nt stopped it eating I,ll just keep a check on the poor thing and let you both know if it improves ...

Thank you Janette...please do...being the softie that I am will probably be worrying about this little bird in the days to come.

oh dear agree with all of you....hope it improves quickly....arent' we big softies when it comes to our birds?

Lol Lw :)
I wondered if it might be from scrapping with another bird over territory,I shouldn't think its flown into a random twig :))

Have,nt see this great tit about today ladies ,been looking for him but nowhere to be seen .I just hope he,s sitting somewhere quiet healing his poor head ....
you are probably right about a fight Aster..... it,s like a battlefield out there these days .... all looking for mates and territories ...today it was the robins having a good old scrap....