My outside garden tap has snapped off from its brass hose union leaving a piece of the taps thread inside the pipe. I need a tool that can get inside the pipe to grip/ turn and remove the threaded piece remaining, can you advise what tool is god for this job ?

They make a tool for plumbing, like a large easy out, will see if I can find.

Here is the easy out type:
Easy Out Nipple Remover

Here is the other type:
Sprinkler Nipple Extractor | Plumbsource.net