Len, who left the show last year, hinted Joe McFadden took the title due to his popularity and not his skill.
As always in the final the judges - Shirley Ballas, Darcey Bussell, Bruno Tonioli and Craig Revel Horwood - marked all of the performances out of 40 but their marks did NOT count.
At the end of the night, Alexandra was on top of the scoreboard with a total of 119 points, scoring two perfect 40s.
However it was Joe who won Strictly Come Dancing 2017 in the results show, where viewers had all the power.
Reacting to the result this week, Len told ITV's This Morning: "I thought the final was great, I enjoyed it very much, there’s a balance, probably Alex was the best dancer... Joe, what a journey he had, he got through because of his popularity, and that’s lovely."
He added: "The judges give their input, the viewers have theirs, it’s marvellous."
Meanwhile, Len insisted he wasn't a "traitor" for quitting the BBC series and continuing with the American version.
He explained: "People got very, very anal about this, saying 'the traitor'. It was all to do with my contract, it’s an annual thing. The BBC only do one year - they can hire you or fire you.
"In the US they sign you up for four years. I thought do I want to fly every week back to Britain from LA? I could not physically do it.
"It’s an 11 hour flight, eight hour time difference. You’re there two days and then you’re back."