A computer glitch that has halted all US visa applications is expected to remain until next week, a government spokesman said last night.
The global technical problem has hit business travellers who need a working visa, leaving them unable to fly.
In London, the US embassy in Grosvenor Square has not issued visas for more than a week, leaving business travellers who need a working visa unable to fly.
US State Department spokesman John Kirby said: "Our Bureau of Consular Affairs continues to experiences problems with the visa system. This is a global issue and we're working around the clock to fix it.
"That said, for all the hard work, don't expect the system will be on-line before next week."
The fault is reportedly affecting computers that deal with the security-related biometric checks at embassies. As this data is mandatory in processing applications, the failure has hit the entire system.
US officials said there is "no evidence" the breakdown, which started on June 9, was the result of a cyber-attack.
Graham Smith