Billionaire businessman Mike Ashley today bought a 41.6% holding in Newcastle to launch a takeover bid.
St James' Holdings Limited, a company set up specifically to buy shares in the club, has acquired 55,342,223 shares at 100p each from Wynyard (Guernsey) Limited, Cameron Hall Developments Limited and Cameron Hall Developments Limited Executive Pension Scheme, the holdings of Sir John Hall and his family.
Stock Exchange rules mean that the company now has to make a cash offer for the remaining shares, around 29.8% of which belong to chairman Freddy Shepherd.
Sir John will remain as the club's life president, although the man who succeeded him as chairman, Shepherd, now faces a major decision over his continuing involvement.
Ashley said: 'I am delighted to have this opportunity to invest in Newcastle United.
'The club has a fantastic infrastructure, for which Sir John and the board must take much of the credit.
'I am pleased that Sir John has agreed to remain as life president of the club.
'Newcastle United has a wonderful heritage and the passion of its fans is legendary.
'I am sure that, like me, they are already excited about the prospects for next season under the new manager's stewardship.'
Sir John, who formed the Magpie Group to take over the club back in the early 1990s, stood down as chairman in 1997 and believes the time is now right for new blood at St James' Park.
He said: 'I have been associated with the direction of Newcastle United for nearly 20 years.
'In that time, I have led the club and, before I retired, led the team responsible for the modernisation of the club we all see today.
'It is now time for me to move on and let others take up the challenge of competing in the global marketplace.
'Mike Ashley is a major player in the sporting world and I am convinced that he is the right person to take my place and take the club forward.
'I am sure he will be good for the club and its loyal fans and indeed for the region.
'I wish him the very best and hope he enjoys it as much as I have.
'Finally, I would like to thank all the fans for their support whilst I was at the helm and would ask them to lend the same level of support to Mike. He has my full backing.'
Interest in Newcastle has been rife for some time and Shepherd has fought off two approaches in recent months, one by the Jersey-based Belgravia Group and the other by the Polygon-backed St James' Park Group.
He has insisted in the past he would not stand in the way of a 'Geordie Abramovich' who wanted to pour millions into the club.
Today's news will come as a boost to Shepherd's critics, who have been calling for change for some time, but it remains to be seen just how the latest development will affect his position.