"For Wales - see England" was the notorious reference in old versions of the Encyclopaedia Britannica.

Clearly attitudes like that went some way towards creating support for Welsh nationalism, but were some of those prominent nationalists also supporters of the extreme right?

There have long been accusations that the founding fathers of Plaid Cymru were sympathetic to fascism.

Prof Richard Wyn Jones, who is the director of the Wales Governance Centre at Cardiff University, has just published a book which looks at the subject in detail.

He spoke to Vaughan Roderick on BBC Radio Wales' Sunday Politics programme.