Mercer, the 66-year-old controlling shareholder in Netlon, is the last of Blackburn's trio of entrepreneurs after the steel magnate Jack Walker sold up and became the sugar daddy of Blackburn Rovers football club.
Netlon is a tubular plastic mesh now found in the world's fruit markets, hospitals and garden centres. It has been a runaway success and later forms of the mesh have been used for stabilising ground and sports turf. Netlon's mesh now lies under the bombed runway at Port Stanley, racetracks in Hong Kong and Santa Anita, California, and the Rovers' pitch at Ewood Park.
The production process had humble origins. The first dies for extruding the plastic mesh were tested on mashed potato fed through a kitchen mixer before Mercer patented the process and went into production on his own account.
The Shirley Institute, arbiter of textile matters, defined his invention as only 'the ninth generic textile process' developed since the Stone Age. He retained control, selling licences to Dupont and Mitsui, and now holds 28 personal patents to the process.
Like Sir Alistair Pilkington, who pioneered the float glass process, Mercer won the Royal Society's Mullard Medal award in 1974. Salvador Dali was intrigued by the touch qualities of Netlon and painted Mercer's portrait.
But now it seems Mercer may have had enough. Word of the possible sale has leaked from some of the Blackburn workers who feel that they may become the pawns of an international owner.
Speaking from the suburban villa that is Netlon's HQ, chairman Roger Duckworth was playing down the stories.
'It is true that Dr Mercer is 66 and must soon consider his future. But nothing, absolutely nothing, has been settled.'
The statement from the quiet inventor himself was even more cryptic: 'There is a distinct possibility that I will be working for Netlon for at least the next five years.'