A UK identity card scheme has moved a step closer after No 10 confirmed a draft bill would be published shortly.
Blair says ministers have won over civil liberties concerns
On Sunday Trade Secretary Patricia Hewitt said there had to be evidence that making ID cards compulsory had "additional benefits".
But Tony Blair's spokesman indicated the prime minister saw ID as a key weapon against international terrorism.
"There are logistical questions that still remain ... those are going to be worked on," he said.
He added: "But at the same time, we will publish a draft bill this session, soon and Parliament will have its say."
The spokesman was asked if the prime minister believed that the only concerns about ID cards in the cabinet were practical ones.
He replied: "Cabinet ministers are perfectly entitled to speak for themselves.
"What the prime minister was recognising is that there is an issue here which we are addressing and do need to address in the light of outrages such as Madrid
and the threat posed to this country.
"That is why the issue was placed on the agenda in November and is being addressed in the way it is."
Last week Britain's top police officer backed calls for the quick introduction of ID cards and criticised Ms Hewitt for saying it will take "many years", branding her "wrong".
That followed Mr Blair's monthly news conference where he said identity cards would be introduced "more quickly than even we anticipated".
Change of heart?
He said then the government had won over those who opposed the controversial measure for civil liberties reasons.
Practical issues and logistics were the only things stopping the introduction of ID cards, he said.
In his interview Sir John said: "Up to a year and a half ago I would have been against identification cards because we had no certainty that the documentation used for identification cards could actually prove with certainty the identification of someone.
"Biometrics, the use of eyes, the use of fingerprints is now a certainty in a way that never was before so therefore identification either whether it be on border controls or whether we have to deal with stop and search in the street, anti-terrorism kind of activity or even along the normal way that police officers work would give a certainty we need."
On Ms Hewitt's remarks about ID cards he said he "disagreed totally" with the trade secretary, adding that the sooner the legislation was passed the better.