The sale of AIA, an Asian asset owned by American International Group, for $35.5 billion was agreed in principle earlier this year, but the deal has been complicated by the struggle of Prudential's CEO Tidjane Thiam to convince shareholders of the value of the investment.
According to a report in the Financial Times, Mr Wilson feels that his position would be untenable if the agreement goes through, describing the planned merger of the two firms as "unworkable" to friends and industry executives.
An inside source told the newspaper: "Mark remains loyal to AIA, but doesn't plan to stay with the merged group because he feels it is a disaster waiting to happen."
Prudential needs the support of 75 per cent of its shareholders in a forthcoming vote for the deal to go ahead.
By Asim Shah