The Sunday Times reports that the Middletons will be footing the bill for hotel suites (over £20,000), bridal gowns (around £30,000), bridesmaids' dresses, the maid of honour's outfit (around £20,000) and the honeymoon.
Clarence House refused to confirm the figure, stating: "The Middletons have offered to contribute to the cost of the wedding. How much they contribute is a private matter."
Anyone who has helped organise a wedding (even one that's not being live broadcast to the nation) will know that once the big ticket items have been dealt with there are hundreds of little things which ramp the price up yet further.
If we were the Middletons we'd be hoping that the Mountbatten-Windsors will be taking care of the sugared almonds and the confetti.