The supermarket giant’s non-executive chair says if the UK and EU fail to agree a Brexit deal factors such as tariffs “almost inevitably are going to lead to higher prices and I think if we go out on a no-deal basis that is unavoidable”.

Speaking to Bloomberg TV, Allan warned that tariffs on some food products are “quite substantial” and may encourage shoppers to buy more domestically sourced alternatives – such as eating cheddar rather than French cheese, which he said can come with tariffs “as high as 40%-plus”.

Allan forecasted that the price increase of the average shopping basket in the event of a no-deal Brexit would be between 3-5%.