Theyll also hear from the former subpostmaster whos led the campaign for justice.
The ceremony was delayed from September because of the US actors and writers strikes.
Two Tory deputy chairmen are vowing to join the rebellion.
Its a crucial first step in his bid to return to the White House.
In our weekly From The Newsroom opinion piece, editor Jeremy Ransome talks of his love for our park and the important role it has played in his life.