A Which? investigation into the percentage of Christmas card pack prices that major retailers donate to charity has found that the Co-Operative and Lidl give the least - 7 and 8 per cent respectively.

In an investigation into 13 top retailers, published yesterday, the retail consumer charity said that the Co-Operative donates 10p (7 per cent) of the £1.50 pack price to food poverty charity Fare Share.

Supermarket Lidl gave 10p to CLIC Sargeant – around 8 per cent – of its £1.19 pack price.

WH Smith topped the list, as the retailer donates 100 per cent of some of its charity cards to Children in Need. However the stationary retailer has arrangements with other charities which see it donate only 10 or 20 per cent of pack price sales to charities like Help for Heroes, the RSPCA and Marie Curie.

Which? also found that Morrisons – who is selling cards for Sue Ryder – will be donating £50,000 to the care charity regardless of how many packs are sold. Tesco is also selling a range of Christmas card packs and will be donating a total of £300,000 to Diabetes UK and the British Heart Foundation.

Which? editor Richard Headland said: "There are real differences between how retailers donate to good causes, so people may want to look out for this if they are planning to buy charity cards this festive season."