In the same interview, a former colleague of the US evangelist, who died at his home in North Carolina at the age of 99 yesterday, also dismissed the idea of unveiling a statue in his honour.
Harvey Thomas, who spent 15 years working on Graham's evangelistic events around the world, told Premier: "Billy would not want any kind of physical memorial in that sense.
"I think he would rather see a service of thanksgiving for what God has done than a memorial service for what Billy Graham has done - he was very definite on that."
While suggesting St Paul's Cathedral could be a fitting setting for the memorial ceremony, Mr Thomas added that "nobody knows" so far whether it will come into fruition.
He added: "Whether things will happen, I have no idea at this particular point because I think it would probably depend entirely on Franklin Graham or the family as to what they wanted to do, or the Billy Graham Evangelistic Association maybe."
Thomas said that he wanted to see other preachers learn from Graham's strong work ethic and the trust he showed that God would meet the financial needs of any work He called him to.
Thomas added: "We worked like Trojans.
"Billy used to say to us 'you [ought to] believe that nothing happens unless God does it but you work as though there is no God' - and that's the bit that's missing in today's world and that's why there's so little in terms of real evangelism.
"Billy started from the point of view 'God is calling me to a crusade or a mission in this place and, if he's calling me... he will provide the funds'."
"Today, it starts with the point of view 'can we get enough money to do a mission here or there?' It's completely reversed."
Click here to listen to Premier's Alex Williams speaking with Harvey Thomas:
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