Hidden in the murky depths of David Cameron's immigration speech were some nasty ideas affecting civil liberties and privacy.

The prime minister, who not so long ago was deploying his best poetic rhetoric against Labour's ID cards scheme, is planning on bringing in what appears to be a new biometric identity system. He only mentioned identity cards for migrants as an aside, but the implications are staggering.

"We are already rolling out a new single secure form of identification – the biometric residence permit - for those from outside the EEA to make it easier to identify illegal migrants in the first place," he said.

This is curious. There is already a biometric ID programme for some non-EEA nationals, depending on the risk category the UK Border Agency puts their country in. What does he mean? Is he expanding it to include all non-EEA nationals, or introducing a new system, or just hyping a pre-existing system so he can look tough on immigration?

The current system is a remnant of the ID cards programme. In 2009 it was split in two, so ministers could preserve some of their efforts in case the ID cards plan was scrapped, which it was. Section one was the national identity register, section two was biographical footprint data and section three was the national biometric service. This was kept and the infrastructure for it was pretty thoroughly embedded. Most Post Offices have booths where they will take your fingerprints, for instance.

The migrants who have to have these cards can theoretically be asked to provide it to immigration officers. Beyond the civil liberties implications, it does real damage to the economy. A couple of years ago students coming to the UK from Pakistan - many of them wealthy and heading for institutions like Imperial or Oxbridge – were forced to go to Dubai to have their biometric details taken. UKBA decided it wasn't going to open a branch in Islamabad because of risks to its staff. We can only imagine how many foreign students decide it's not worth the effort.

Once you allow these infrastructures to exist there will always be some clever politician popping up to suggest it is turned to some use, such as in criminal record bureau (CRB) checks. Nick Clegg's speech on immigration last week was quickly followed by the news the coalition would look into forcing Bulgarians and Romanians to take biometric identity permits when they are eventually allowed into the UK. That policy would flatly contradict EU rules.

The Home Office haven't got back to me yet on what Cameron's off-hand biometric comment meant. I'll update when/if I get it. Either way, it's ugly stuff a million miles away from his promises before entering Downing Street.

The second ugly implication of Cameron's speech concerns landlords and letting agents, who will be asked to check the documents of their potential tenants.

"I now want us to make sure private landlords check their tenants' immigration status with consequences for those rogue landlords who fail to do so," the prime minister said.

What an ugly world he envisages. Brits would also be checked, of course, but Cameron urged us not to worry. You'll just have to flash your passport or driving licence and carry on.

The reality is Cameron is expanding a system where you have to show your documents – prove your identity – while going about your daily business. This is the system of constant checks and monitoring which Labour envisaged: the need to constantly prove to the state you are legitimate, rather than the other way round.

It's not even effective, because the sector is unregulated. Unaccredited landlords and letting agents will carry on regardless and illegal immigration will make sure they know who they are. Cameron's plan spreads suspicion and the database state, while encouraging a black market in rental housing.

And for what? To satisfy the ignorant nonsense of a section of the public. There is no immigration problem in the UK. Immigration is a net contributor to the economy. There is a housing problem, certainly, but it is not to do with immigrants. It is to do with the lack of social housing stock following the 'right to buy' revolution in the 80s which Cameron is so sentimental about.

Draconian immigration policies almost always conceal an affront to civil liberties. Cameron barely even bothered hiding it today.

We're a long way away from his pre-election love letters to British liberties.