The 34-year-old shocked the industry in August when he announced his intention to retire by the end of the year, and it had been expected his final ride had come in the early hours of Sunday morning when he could finish only seventh aboard Trade Storm in the Hong Kong Mile.
Twice crowned champion jockey in Britain, Spencer was told in the summer his retained contract with influential owners Qatar Racing would not be renewed in 2015 and he was set to take up a management role within Sheikh Fahad Al Thani’s racing operation.
However, he said in a statement: “Sheikh Fahad and Qatar Racing offered me a wonderful opportunity to become part of their management team but, after much reflection, I have decided that at this stage in my life I am not going to accept it.
“I have discussed at length with Sheikh Fahad my decision to carry on riding and he fully understands and supports me. He appreciates that riding is what makes me happy and the last thing he wants to do is stand in the way of that.
“The friendship I have with Sheikh Fahad goes way beyond that of the traditional owner-jockey relationship and even though I will no longer be retained by Qatar Racing I know that won’t change. I will be riding primarily as a freelance, but obviously I have certain existing links and relationships with trainers that I will be utilising. I am also looking forward to being entirely free and available for the first time in six seasons and developing new associations. I have no specific targets other than to continue to be successful.
“There have been a few close confidants that have helped me in making this decision and I’d like to thank them for their support.
“At the time of their offer, I thought I was ready to retire from race riding and take up a position with Qatar Racing. Sheikh Fahad understands completely why I no longer feel I can accept the offer and that is what is most important to me, I am less concerned about what others may think or say.”
One of the highlights for Spencer this season has been his association with the Jamie Osborne-trained Toast Of New York.
The pair teamed up for glory in the UAE Derby at Meydan in March and came within a nose of beating Bayern for a fairytale win in the Breeders’ Cup Classic at Santa Anita last month.
The horse is due to run at Meydan next March, where he will contest the world’s richest race, the Dubai World Cup.
Osborne said: “If it means that he is going to be available to ride our good horse, that’s obviously great news and I’m delighted.
“I always felt that maybe the decision (to retire) was, perhaps, slightly knee-jerk and I hoped that given more time to reflect he could change his mind.
“He obviously has done that and I’m delighted he has.”
Newmarket trainer Michael Bell is a long-time ally of Spencer, with 2009 Epsom and Curragh Oaks winner Sariska among their many triumphs.
Bell said: “We have worked together closely for the last eight years one way or another and I’m sure we’ll carry on in the same vein. At the time I felt his initial decision was a bit hasty and the closer it has got to the end of the year, I think reality has hit home and Jamie has realised how much he would miss it.
“With horses like Toast Of New York to ride, to name just one, it’s no surprise he’s decided to carry on and I’m sure he’ll get a lot of support.
“Jamie is a very rare talent.”
What at the time looked like being Spencer’s final Group One victory had come on Just The Judge for Charlie Hills in the E.P. Taylor Stakes at Woodbine in Canada in October.
Hills said: “He’s far too young to retire. I think he probably still got a great 10 years left in him.
“We’ve had some great success in the last couple of years together with Sheikh Fahad’s horses, and others, and I’m sure we’ll continue to support him.”
One of the most talked-about members of the weighing-room, with his protracted riding style having continually divided opinion, Spencer became the youngest jockey to claim a major European Classic when he won the Irish 1,000 Guineas aboard the Tommy Stack-trained Tarascon in 1998.
He also landed the 2003 St Leger at Doncaster with Brian Boru.
Champion Irish apprentice in 1999, Spencer had his first competitive winner at Downpatrick in 1996 before returning to Ireland in 2004, when he was crowned champion jockey under the tutelage of Aidan O’Brien.