Cherie begins £90,000 American lecture tour to help pay the mortgage

Cherie Blair will begin paying off the Blairs' £3m mortgage today with the start of her money-spinning lecture tour of America at a ladies' luncheon in Sulphur Springs, West Virginia.

Cherie Blair will begin paying off the Blairs' £3m mortgage today with the start of her money-spinning lecture tour of America at a ladies' luncheon in Sulphur Springs, West Virginia.

The Prime Minister's wife, who is expected to earn £90,000 for three speaking engagements in the United States, is sharing the billing at an annual forum for insurance agents with Paul Bremer, the US ambassador who headed the provisional government in Iraq, and the former Soviet president Mikhail Gorbachev.

As the UK's "First Lady", Mrs Blair has proved to be big box office after hiring a leading East Coast agency for celebrity speakers. She is replacing the actress Lauren Bacall who pulled out of the lunch for the Council of Insurance Agents and Brokers conference.

Politicians at Westminster were bemused by her decision to tour America, but reports that the Blairs are buying a £3.6m town house in Connaught Square may explain her cashing in on the speaking circuit.

Mrs Blair can earn more than £100,000 a year in her legal practice as a leading specialist on civil rights and company law. Mr Blair is hoping to pay off their mortgage with his own speaking tours of the US, following in the footsteps of John Major and Baroness Thatcher, but that must wait for his retirement from frontline politics.

The Blairs are understood to have put down a deposit of about 10 per cent, £360,000, drawn from savings, investments and the proceeds of the sale of their home in Islington in 1997. Stamp duty, at 4 per cent, would have cost £144,000, with solicitors' fees and survey costs adding an estimated £10,000.

Mrs Blair has two further US lecture dates this month: one to the American Bar and the other to Harvard University.

She has recently co-authored a book on life at No 10 called The Goldfish Bowl and today's event is eagerly awaited by the organisers, who say the lunch is traditionally "just entertainment". According to one weekend report, when asked whether Mrs Blair would be expected to talk about "life at No 10" and "family life", the organiser replied: "Oh yes, because these are all spouses of pretty high-powered men."

Mrs Blair may disappoint her audience, however, if they are anticipating anecdotes about living next door to Gordon Brown. She has promised to focus on her specialist subject of civil rights and the law.