Holborn has a history of working on football takeovers, having advised on deals for Manchester United, Southampton and Aston Villa in recent years.
But Shinawatra is a controversial figure -and his human rights record was scrutinised when he made advances for Liverpool FC while still PM two years ago. At the time, his background was cited as a key reason for the deal falling through.
Despite being deposed in a bloodless military coup last year, Shinawatra's interest in buying an English football club remains. Thailand is noted for its vociferous support of English football and is home to one of its largest overseas fanbases.
Holborn chairman David Bick said he intends to focus on Shinawatra's financial clout, which he claimed would be City fans' main concern.