The chairman of airports operator BAA and his wife were robbed of £50,000 worth of jewellery by armed thieves who barged into their central London home.
Sir Nigel Rudd and his wife Lesley were attacked as they returned to their Belgravia home at midnight on Monday.
Two men, armed with a knife, "forced their way in" as the victims were closing their door, police said.
The couple were said to be left shaken by the attack but were not hurt. No-one has been arrested over the attack.
A Metropolitan Police spokeswoman said: "The victims had returned to the address minutes before and, as they were closing the front door, two men forced their way in behind them.
"The suspects, who are described as black, threatened the victims with a knife and made off with high-value goods, including a quantity of jewellery and a watch."