Danny Cipriani has been dropped from the England team for Saturday's Calcutta Cup clash against Scotland at Murrayfield.
The 20-year-old Wasps star has been omitted for what the Rugby Football Union have termed "inappropriate behaviour last night".
The matter is believed to revolve around Cipriani being pictured leaving a London nightclub after midnight.
He is replaced in the starting line-up by Gloucester's Iain Balshaw, who had originally made way for Cipriani to make his full England debut.
Balshaw's place on the bench goes to Sale Sharks fly-half Charlie Hodgson. Cipriani, whose England career could now lie in tatters before it has barely started, will not travel to Scotland with the England squad later today.
The RFU say no further disciplinary action will be taken against him but he has been warned and advised about his future conduct.
England head coach Brian Ashton said; "I have taken the decision regarding Danny and the matter is now closed. I will keep an open mind on selecting him for future games."