The claims that Mr Mair had allegedly bought a number of manuals from an extremist group in the US was uncovered by the Southern Poverty Law Centre (SPLC), a civil rights organisation in the US. It said Mr Mair made the purchases between 1999 and 2003. Receipts for items also included Ich Kämpfe, an illustrated handbook issued to members of the Nazi party in 1942.

Mr Mair’s transactions showed he spent $150 in 1999 buying a book of artwork thought to be of Adolf Hitler’s paintings and drawings; a book on Aryan mythology; and two other neo-Nazi tracts.

In total, SPLC said Mr Mair had spent £430 worth of books and manuals from the National Alliance, a white separatist movement which shut down in 2013. The National Alliance was set up by William Pierce, one of whose racist novels is said to have inspired Timothy McVeigh, the Oklahoma City bomber who murdered 168 people and wounded more than 600 in the 1995 atrocity.

It was reported on Friday night that special police units which searched Mr Mair’s house were believed to have found samples of Nazi regalia and far-Right literature.

One neighbour on Friday spoke of her surprise at reports that Mr Mair had purchased neo-Nazi books and other materials.

“If you had told me he had turned into Father Christmas I would have been more likely to believe you than him turning out to be a neo-Nazi,” said Diana Peters, 65, who had known Mr Mair for many years. She said he had taught migrants English at a college in Dewsbury.