A British operator could mean many different things...
Jet2 - Do they need to expand via a ready made low cost airline?
flyBE - Do they have the money?
Thomson - Why do would they need a low cost airline?
Monarch - Seem to have a cautious approach...
British Airways buying both baby and mainline? Doesn't look logical, but you never know...
Virgin - maybe looking at relaunching European holidays?? - Virgin Sun?
Stelios?
Management buy-out/venture cap?