Bradford Council is proposing to remove all its funding for the Festival and a campaign is underway to try and persuade councillors to change their minds.
That campaign has now received words of support from Mr Simpson, best known for his reporting on conflicts around the world for the BBC, who has previously spoken at the event.
In a letter to Keighley MP Kris Hopkins, Mr Simpson wrote: “I have very pleasant memories of it, and I remember a couple I met there telling me how important the Festival was for the entire region, and how it kept them in touch with the arts and cultural life of the UK and the wider world.
“Festivals like this play a big part in the life of a community, and I very much hope the decision to cut the funding will be reversed.”
Bradford Council has to find savings of £41 million in the coming financial year as it deals with cuts in grants from central government.