The Queen is expected to increase her financial support for the Earl and Countess of Wessex following their decision to give up their businesses.
Edward has a personal fortune estimated at £9m (€14.7m) but that is unlikely to cover the costs of keeping up appearances as major public figures.
The couple’s sprawling 50-bedroom mansion at Bagshot Park, Surrey, is roughly three times the size of the Prince of Wales’ Highgrove estate and is the largest residence of the Queen’s children.
The spiralling cost of keeping it running is now said to total £250,000 (€410,000) a year.
Some of that has been recouped by basing Edward’s company Ardent in a converted stable block in the grounds at a reported rent of £50,000 (€82,000) a year, a sum said to cover Edward’s basic rent from the Crown Estate.
But that rent will go when the Earl severs his ties with the firm, along with his £65,000 (€106,000) salary.
His wife Sophie sacrifices a similar salary by giving up her role in the RJH public relations firm she founded.
The Queen already refunds the £141,000 (€231,000) the couple receive from the Civil List from her own taxed private income from the Duchy of Lancaster.
Charles receives an estimated £7.5 million a year from his Duchy of Cornwall estate and pays 40% tax on his earnings.
When he suggested his brother and Sophie try to live on Edward’s £141,000 (€231,000) annual annuities from the Queen and his savings, Sophie is said to have replied: ‘‘We don’t have a duchy to fall back on.’’
However, the Queen reportedly gave Edward a private £100,000 (€164,000) pay rise when the Prince William filming controversy raised fresh questions over his business activities last year.
That would bring his income up to the £241,000 (€395,000) paid to his other brother the Duke of York.
And there were suggestions that there could be more help from the Queen when reports that the couple were to drop their business interests first surfaced at the end of last year.
Such details are likely to remain confidential, with a spokeswoman insisting they were a private matter.
‘‘The Earl and Countess are not being funded by the public, by the taxpayer, so how they support themselves is a matter for them,’’ she said.