The International Monetary Fund's loan to Argentina in August 2001 is now generally reckoned to have been a graveerror (although not everyone involved at the time accepts that view).
Lord McConnell, Mr Salmond's predecessor as FM, said that it had been a "grave error" to delay the referendum until 2014 - but he argued that it would be a mistake to challenge and thus undermine the deal between Mr Salmond and Mr Cameron.