Since this thread has inevitably crept onto the subject of turn backs ( although as BV has mentioned, an engine failure has yet to be confirmed).
Its worth remembering that a reasonable number of vintage jets continue to fly. It’s increasingly difficult to keep the seats live in these aircraft so turn backs are very definitely a skill that those operating such aircraft need in their toolbox.
As has previously been mentioned a successful turn back onto the reciprocal runway could usually be achieved in a JP from 160Kts/600ft agl. It’s also important to remember that this is the “gold plated “ solution and that the ACTUAL aim of the manoeuvre is to put the aircraft anywhere on the airfield, wheels up or down since the airfield is usually more hospitable than the terrain surrounding it.