I am travelling to Miami this month. A colleague said the US security rules have recently tightened up. Can you shed any light on this? - Becky Ross
Since the dreadful events of September 11, 2001, the United States has - perhaps understandably - made it progressively tougher for people to have a holiday, or travel there on business.
The authorities are haunted by the knowledge that the 19 terrorists who destroyed so many lives were legally admitted to the US.
The key step for a short visit to America is to obtain permission, online, to board a plane to the US. For this you need to go to cbp.gov/esta - rather than any of the sites that purport to be official sites and charge additional fees. The current cost is $14, which applies whether or not your application is granted.
Most tourists qualify but anyone with a criminal record is obliged to apply for a visa - an expensive and stressful process involving close questioning at the US Embassy in Grosvenor Square - with no guarantee of success.
Assuming you get permission, the next step is to book your flight. For this, the authorities demand a lot of personal information. They then check all your personal details against "watch lists" to try to prevent a repeat of events such as the attempted destruction of a transatlantic plane by the so-called underwear bomber on Christmas Day 2009.
But if you want to visit the US, you have to toe the line.
Simon Calder is senior travel editor of The Independent
Email your travel queries to [email protected].