@gilesdavies quotes "
I have never seen this happen before, but is quite a novel way of maximising runway usage at peak times".
Be assured that the scenario of one aircraft back tracking to a turning circle and another aircraft entering the runway from a taxiway for immediate departure is 'very typical' now at Luton.
I see this scenario daily (from my lounge) but separation exists in that the aircraft at the circle is not allowed to depart until the other aircraft is well ahead!
As I have stated in previous threads I have seen Boeing 777's and A300's departing from taxiway intersections of Luton's runway which in effect means they do not need full length runway use to gain rotation.
But equally I have witnessed two aircraft too date literally rotating feet from the turning circles!