Yorkshire Tea may also be examined for any potentially problematic links.

       A leaked council document states: "Historically, some of the ingredients used to make these 'local' products were gained through the slave trade (for example, sugar)."

       The document also says - under the heading "activity in relation to Black Lives Matter" - that investigations into these treats will explore "how local products such as Yorkshire Parkin and Yorkshire Tea are, in fact, reliant on global trade".

       The findings will be used to teach primary school pupils that while Yorkshire's products put the county "on the map", some ingredients "would have been sourced from around the empire and involved the labour of enslaved people".

       The Key Stage 2 materials will be added to the Leeds Curriculum set of teacher resources. It includes an Empire and Colonialism section, covering the Windrush scandal, slavery, gender bias and decolonisation.

       But ex-MEP James Carver said: "When this is happening in Yorkshire we have to assume the world truly has gone mad."