The number of forged passports spotted at British ports and airports has fallen by almost half over the past five years, it was revealed today.
Some 1,858 fakes were detected by border officials last year, down from 3,300 in 2007, according to figures obtained by the BBC under Freedom of Information legislation.
The UK Border Agency said that the introduction of biometric data had made it more difficult for criminals to forge documents.
And UKBA chief executive Rob Whiteman said more effort was being put into checking passports before people arrive in the UK.
But House of Commons Home Affairs Committee chairman, Labour MP Keith Vaz, warned against complacency over passport faking.
Mr Whiteman told BBC Radio 4's World This Weekend: "Overall - looking at the total amount of forgeries detected - we're doing a good job in that we're constantly finding more forgeries overseas.
"The amount, therefore, that we detect at the border, there is a long-term trend of that falling but that's because we're so successfully finding it overseas and stopping forged documents getting to the UK in the first place.
"Staff on the border are trained in detecting forgery. They have a lot of very good skills, they have technology that assists them to do that, they have experience and we train them in order to have the confidence to question any cases where they think there could be suspicion.
"So I genuinely think that the interpretation that we are getting more successful in detecting forgery is correct."
Asked whether planned cuts of 5,000 in staffing numbers by 2015 were making Britain more vulnerable to fake passports, Mr Whiteman said: "We will see staff reductions in areas where we can become more efficient - the way that we handle documents in our back-office processes.
"Like any large organisation, we have the scope to become more efficient in the way we do case-work."
Mr Vaz told the programme: "The concern is that one becomes complacent and one believes that the reason why the number of people that are stopped for having forged documents has decreased is because everything is going well.
"The worry for me is the fact that people are finding more sophisticated ways of getting in.
"I don't believe the human traffickers and those who want to come to the United Kingdom looked at the figures in 2004 and found there were 10,000 spotted and then decided 'Well, we're just going to go away'.
"Unless you have ... good security equipment but also you have the people who are able to interpret when a forged passport is a forged passport, then there is a danger of looking at these figures and being complacent about them."