Anglepoise lamp bulb socket replacement Help

[JD2012]

i need advice on replacing my Anglepoise type Lamp socket replacement.

The lamp is over 20 years old and when I put a bulb in it flashes as its not getting a proper connection.
Its a bayonet type fitting. I think the plastic in the bulb lamp socket has gone brittle with age.

I checked the plug etc and its all O.K.

What sort of socket do I need to replace it?

Thanks

Here are some pictures of the lamp. It has a switch on the middle in the back where the holder is screwed in shown in picture 2.

 

[ericmark]

Seem to remember the diameter of bulb holder was larger than normal, seem to remember ikea did the larger bulb holder.