Mr Scott-Kerr said working with Forsyth had been "one of the great pleasures of my professional life".
"The flow of brilliant plots and ideas aside, he was the most professional writer an editor could hope for," he said.
"His journalistic background brought a rigour and a metronomic efficiency to his working practice and his nose for and understanding of a great story kept his novels both thrillingly contemporary and fresh. It was a joy and an education to watch him at work."
Singer Elaine Paige, a friend of Forsyth, said she felt "total sadness" at the news of his death.
"His academic knowledge of places, palaces and geography was bar none," she wrote on X. "He'll be much missed for so many reasons."
English composer Andrew Lloyd Webber, who worked with Forsyth on Love Never Dies, the follow-up to Phantom of the Opera, said: "He really understood the romance and thrills which make the Phantom such an alluring character.
"Thank you Frederick, for creating stories which will live on for generations in your honour."
And Conservative MP Sir David Davis said his "great friend" was a "terrific man" and a "fabulous wordsmith".
"He was a great believer in the old values - he believed in honour and patriotism and courage and directness and straightforwardness and [was] a big defender of our armed forces," he told Sky News.
Forsyth followed The Day Of The Jackal with The Odessa File in 1972, which was adapted for the big screen in a film starring Jon Voight two years later.
The author had written a follow-up, Revenge of Odessa, with fellow thriller writer Tony Kent, which will be published this August.