Margaret Thatcher insisted on paying nearly £2,000 towards the search for her son after he went missing in the Sahara Desert amid concerns of a public backlash over taxpayers' money being used, newly released files reveal.
Mark Thatcher went missing for six days in January 1982 during the Paris to Dakar car rally, along with his French co-driver, Anne-Charlotte Verney, and their mechanic. They were eventually found after a search by the Algerian military.
Help was also offered by the French and Mali governments, while Denis Thatcher flew to Algeria himself. Records released for the first time to the National Archives in Kew, west London, show that Mrs Thatcher paid a total of £1,784.80 for the search operation to avoid any criticism over costs to British taxpayers.
Mr Thatcher, who had not been seen since January 8 1982, was rescued by an Algerian military aircraft on January 14. But amid relief that he had been found, private discussions between the Foreign Office and Number 10 soon turned to how the cost of the operation should be covered, as journalists and MPs pursued the issue.
A letter sent to the Foreign Office on January 29 asked for the figures involved so questions could be answered, prompting a list of charges including hotel bills, air fares, telegrams and phone calls and subsistence.
One document showed that bills at the Tahat Hotel in Tamanrasset for a group including Mark Thatcher, Ms Verney and Denis Thatcher exceeded 11,500 Algerian dinars - a third of it made up by drinks - although the bill was later waived and the party was told there was nothing to pay. In a telegram to the Foreign Office, one aide reported that the bill almost certainly included "the liberal dispensation of drinks to all and sundry after Mark Thatcher's arrival at hotel".
A statement of Foreign and Commonwealth Office (FCO) costs of the operation included air fares, subsistence, accommodation for a Swiss rally team which helped with information on Mr Thatcher's possible whereabouts, as well as telegrams and phone calls at various embassies.
With the major part of the bill met by the Algerian government, the final bill for Mr Thatcher was originally to be £583.14 - with the taxpayer set to pick up the remaining £1,190.95. Private secretary John Coles said there had been a "number of inquiries from the public and one or two from MPs" about the expense, but by paying the £583.14 they could be dealt with in an "entirely reasonable and justifiable way".
But a memo to the PM on February 12 reveals Mrs Thatcher made the decision to pay the extra sum herself. "In addition, there is the total cost to the taxpayer of £1,191. I think you wanted to consider the latter figure," Mr Coles wrote.
And in a hand-written note, Mrs Thatcher added: "I must pay the £1,191. We can therefore say that no extra cost has fallen on the British taxpayer. To who do I make out the cheque? MT." A final bill for £1,784.80 - made up of slightly amended totals - was later paid by Mrs Thatcher.