Observers have suggested that the total will run into tens of millions of pounds, with one estimate putting the figure at £80 million for security alone.
The likely budget will not be known until the detailed arrangements for the event have been announced.
But
Prince William and
Kate Middleton have already come under pressure to rein in the costs, at a time of severe public spending cuts and high rates of unemployment.
A spokesman for St James’s Palace said the couple were "mindful of the economic situation" and insisted that the
Royal family would pay their share.
“Both the Prince of Wales and the Queen are likely to contribute towards the cost of the wedding. It will be a family contribution but no final decision had been made,” he said.
“In particular, if the reception is held at Buckingham Palace, the Queen will pay for that.”