JK Rowling was denied the US's highest civilian honour because members of the Bush administration believed Harry Potter "encouraged witchcraft", a new book claims.

Matt Latimer, a former speech writer for George W Bush, states in 'Speechless: Tales of a White House Survivor' that White House officials objected to the author's perceived promotion of sorcery in the series.

As a result her name was not included amongst those receiving the Presidential Medal of Freedom, it is alleged.

The award acknowledges contributions to US national interest, world peace or cultural endeavours.