The director of the world's biggest festival, the Edinburgh International Festival, has criticised the tone and process of Scotland's independence referendum as it launched its 2014 programme.

Sir Jonathan Mills, in his final year as the festival's artistic director, said the independence debate had a lack of rigour and a lack of process, as well as being niggly and antagonistic.

Sir Jonathan, whose festival programme does not have any performance directly related to the poll but which, he says, can be seen "in the light" of the vote, said his views on the referendum were coloured by how Australia approached constitutional issues. He said: "What I would observe - and this is an Australian talking - is its lack of rigour and its lack of process.

"If this was a question being put in Australia, the dimension and the style of presentation would be far less partisan and far less niggly and antagonistic.

"Because if there is a view that if you are dealing with a constitutional matter, and there are structures in place... there is a sense that it is above politics, to a certain extent."

He added: "So to me, coming from that perspective, it has lacked that kind of organisational rigour.

"So you get that slightly more rancorous, uncertain and emotional dimension to it.

"I think that there are some statements that have been unfortunate on both sides. They have not elevated the debate to the level I would like to have thought."

Sir Jonathan said he would not reveal how he would vote in the "exciting" referendum, especially as "I might change my mind".

This year's EIF programme features historical plays about Medieval Scotland from the National Theatre of Scotland, art installations about racism and colonialism, ruminations on war and conflict, epic operas, new ballet and dance, classical and modern orchestral music - including one of his Sir Jonathan's own compositions, the Sandakan Threnody.

Sir Jonathan said almost every choice he made for this year's programme, which features the three 'James plays' by Rona Munro for the National Theatre of Scotland (NTS), concerning the lives of James I, II and III of Scotland, could be viewed as a take on the many issues facing Scotland this September.

He said he felt under no pressure, internally or externally, to programme an event or show directly addressing the independence vote, but added: "I think you could interpret these shows in a number of ways and you could interpret them in the light of independence.

"We are not taking a view on it, but we are offering multiple perceptions. This is a great opportunity to look at identity, and the narratives we choose to represent us."

The festival, which runs from August 8 to 31, features 2400 artists from 43 nations, and will be Sir Jonathan's eighth and last.

Many of the events feature the themes of conflict, colonialism and war, as part of the centenary commemoration of the First World War.

The James Plays will star Sofie Gråbøl of The Killing.