Torrential downpours and storms are driving up the cost of Christmas dinner this year amid a washout on the nation’s farms.

The cost of turkey and all the trimmings is up by 6.5 percent to an average of £32.57, according to research by retail experts at Kantar.

The increase is ahead of the wider 2.6 percent price rise across supermarket aisles.

The Kantar figures show particularly steep rises for winter veg. For example, potatoes are up 16.2 percent, while parsnips are up by 12.7 percent and…