Britain's first biometric passports are being issued today.
Each has a digital chip with the owner's precise facial measurements.
The technology will allow port and airport scanners to check that a traveller's features match those on the chip.
Ministers say the new passports are extremely difficult to tamper with or forge and will satisfy American demands for tighter border controls.
Critics counter that the Government is using the passports as a step on the road to compulsory identity cards.
They say the 'stealth' process will end with every Briton needing to produce a hi-tech document before using public services.
By September every new passport will contain the digital chip, with selected passport offices starting to issue them today.
Applicants will not have to visit a passport office in person. Instead their facial dimensions will be scanned from a photograph sent in with their forms.
From October the new passports will be required for visa-free travel to the U.S. Holders of older passports will have to travel to an American Embassy to get a biometric visa.
People traffickers or terrorists could - in theory - apply for a passport using the identity of one person and the photograph of another. The Home Office said it had ways of detecting such fraud but would give no details.
It said all first-time passport applications will have to be made in person from next year. The shake-up will bring Britain into line with international agreements on travel documents. The Government is, however, planning far more ambitious changes from 2008 which would involve a system of iris scans and fingerprints.
The Å51 passport fee remains unchanged but prices will soar if iris scans and fingerprint details are introduced in 2008.
The Government calculates the scheme will cost Å5.8billion over ten years, pushing the price of an adult passport to Å93.
A scathing report by the London School of Economics puts the two costs at as high as Å19.2billion and Å300.
From 2008, passport applicants will also be given an ID card. It is thought that ministers will make ID cards compulsory once around 80 per cent of the population has been issued with one.
Critics have also pointed to grave concerns over the technology. In trials, some scanners struggled to collect biometric data from disabled people and pensioners.
Security experts, including ex-MI5 chief Stella Rimington, have said the cards will be little or no help in the war on terror.
Shadow home secretary David Davis said yesterday that the new passports were 'nothing more than another part of Labour's ill-thought through strategy for the unwanted and ineffective ID cards'.
'Yet again the Government is trying to make compulsory ID cards inevitable, on the very day the Lords are considering the legitimacy of the scheme,' he added.
The ID cards Bill is causing a severe political headache for Labour leaders.
Last month the House of Commons backed the measure by overturning an earlier Lords amendment which would have allowed people to 'opt out' of the ID database when applying for a passport.
The victory saw Labour's majority slashed in half.