SCIENTISTS are hoping to identify the earliest point at which you can tell your friend their ex was a nightmare.
Traditionally-established timescales have proven unreliable, with many people having to retract vile but accurate insults when the relationship restarts.
Researchers have now begun work on a complex formula to calculate the right time to ask a friend what in the name of god they were thinking.
Dr Julian Cook said: “Factors will include length and closeness of friendship and the extent to which the ex was so utterly hellish and unbearable.”
Tom Logan, from Hatfield, added: “My friend finally ended a three-year relationship with her boyfriend when he sold her house to buy a speedboat, which he then crashed into a roundabout.
“I resisted my natural instinct to throw her a ‘thank Christ for that’ party and ended up being accused of negligence because I hadn’t told her that he was a colossal twat.
“Hopefully I’ll have another shot at getting it right as she’s just started dating an ex-squaddie.”