Cherie to earn £30,000 for an afternoon's talk

Downing Street declined to comment last night on reports that Cherie Booth is to earn almost £30,000 for an afternoon on the US lecture circuit this week.

The wife of the Prime Minister will address The Society of the Four Arts in Palm Beach, Florida, on Tuesday, according to The Sunday Times. The event, entitled "An afternoon with Cherie Booth", will earn her £29,000, sources close to the club are reported to have told the newspaper.

Tony Blair was forced to start registering his wife's lecture circuit earnings amid criticism that she was trading on his position as Britain's PM on lecture tours and to sell copies of her book, The Goldfish Bowl. One charity that held a gala event in Ms Booth's honour during a £100,000 lecture tour of Australia last year has admitted it did not give enough of the money raised to good causes.

Ms Booth's latest lucrative booking comes as the couple's mortgage arrangements come under fresh scrutiny. The Prime Minister and his wife are estimated to have home loans totalling £4m, leaving them with repayments of £16,000 a month.

Chris Grayling, the Tory MP who has done most to harry Ms Booth over her earnings, expressed surprise at the latest lecture.

"I had hoped that Number 10 had learned its lesson and realised that her commercial lectures were inappropriate," he said.