The program uses actors and digital manipulation of real footage to show a fictional account of Mr. Bush being gunned down after delivering a speech in Chicago, Peter Dale, the head of More4, told a news conference.
"Death of a President," also scheduled to be shown at the Toronto Film Festival in September, focuses on all those linked to the pretend crime — including nearby anti-war protesters, suspects, Secret Service guards and investigators, Dale said.
More4, which is the digital offshoot of Britain's Channel 4 network, plans to show the program on Oct. 9.
The White House declined to comment on the network's announcement, saying it would not dignify the program with a response.
"It's an extraordinarily gripping and powerful piece of work, a drama constructed like a documentary that looks back at the assassination of George Bush as the starting point for a very gripping detective story," Dale told reporters.
"It's a pointed political examination of what the war on terror did to the American body politic," he said.
Dale said he expected the film would upset some, but defended it as a sophisticated piece of work.
"It's not sensationalist, or simplistic but a very thought-provoking, powerful drama," he said. "I hope people will see that the intention behind it is good."
"Death of a President" is directed by Gabriel Range, whose 2003 TV movie "The Day Britain Stopped" showed what might happen if the country's transportation network ground to a halt.