Mr Greenish joined the Trust in 2006 at a time when the future of the historic Bletchley Park site was in great jeopardy. He implemented a radical recovery programme. Since then, Bletchley Park has been transformed into a secure heritage site with global repute and exceptional prospects.
Mr Greenish said: “The past six years have certainly been challenging but also most rewarding and worthwhile. I have had the privilege of meeting and receiving the support of some extraordinary people.
"I am pleased to be leaving Bletchley Park in such a greatly improved position compared with its previous situation.”
His successor has recently retired from the British Army as a Colonel in the Royal Corps of Signals.
Mr Standen (pictured) said: “Over the years, I have followed the progress of Bletchley Park with enormous interest. I am greatly looking forward to taking on the challenge of leading the Trust as it continues its programme of restoration and development as a world-class museum.”