It’s a hotly debated topic, and whilst the basic purpose – to reduce rush hour traffic – is a Good Thing it has many implications which need to be thought through. These incude the effect on Manchester businesses, house prices, the cost of deliveries, disadvantaging the less well off, increased pressure on public transport and so on.

Quite separately, I want to know why increasingly, the solution to social questions appears to be the installation of more cameras to snoop on law abiding citizens. City centre drunkenness? CCTV will solve that! Worried about knife crime? You won’t mind being watched wherever you go, if it catches criminals, surely? We are way past the thin end of the surveillance wedge, and Britons are now routinely spied on in the interest of law and order.

The Manchester congestion charging scheme encroaches further on our right to be left alone to go about our lawful activities without being watched by the authorities. In order to charge motorists for travelling in a particular direction at a particular time, a network of cameras is needed to watch every road going in to the city. This will be linked to an automatic number plate recognition (ANPR) system which looks up the vehicle’s registered keeper in a database. So they know who you are, where you live and where you are going at what time.

Manchester will have not one but two cordons of these cameras. A vast and complex surveillance system installed not to combat terrorism, speeding, vehicle theft, murder, or any other crime, but simply to ease congestion.

This blow came on the same day she wasted time threatening the culture secretary, Andy Burnham with legal action when she should be out there campaigning for the protection of civil liberties.

Someone should tell Ms Chakrabarti to behave a bit more like RMT leader Bob Crow, and to get over herself.

An overhaul of counter-terrorism laws in 2000 introduced the basic 48-hour detention, extendable to seven days with the permission of the courts. In 2003 that was doubled to 14 days – and the Terrorism Act 2006 took it to 28 days. Can you see a pattern here?

The Prime Minister said it was better to extend the limit now, rather than doing it in a panic at some point in the future. This is superficially attractive – an example of the alternative close often used by sales people. For example, “Would you like to book in tomorrow, or some time next week?” In fact it’s more like a mugger offering to take your wallet now, rather than having to snatch it off you later.

Does it matter to the ordinary law abiding citizen? Won’t they only use it on angry young Muslims intent on violence? In short, yes it does matter. There are already many examples of “function creep” – of anti-terrorism legislation being used to curtail the freedoms of ordinary people. We would do well to remember this famous poem:

First they came for the Socialists, and I did not speak out -
because I was not a Socialist.

Then they came for the Trade Unionists, and I did not speak out -
because I was not a Trade Unionist.

Then they came for the Jews, and I did not speak out -
because I was not a Jew.

Then they came for me – and there was no one left to speak for me.

- Pastor Martin Niemöller (1892–1984)

You may think that airport security is a Good Idea (that’s why workers already undergo police checks and wear ID badges), immigration needs to be controlled, and anything which makes student life easier is to be welcomed (showing two pieces of identification when opening a bank account is a major hassle). But make no mistake – you will be next.

When your personal data is on a vast government database (or a laptop left in a taxi), and you need an identity card just to take the dog for a walk, don’t say you didn’t realise how far the State planned to take this scheme.

I have recently noticed an indicator, like the sugar content in drinks, which is a sure sign that an enterprise is in serious decline. In fact it doesn’t just correlate with the financial performance of businesses, but is a Sugar Test for the very prosperity and integrity of whole countries.

I discovered it on a trip to Spain. There’s a pharmacy near where we stay, and it has always been typical of continental pharmacies – blindingly white, clean, quiet and tidy. The medicines and toiletries are expensive. The staff in white coats are professional, aloof and yet helpful. The green cross sign outside may be a frenetic, dazzling animation more appropriate to Las Vegas than a quiet Spanish street, but inside all is calm and, well, clinical.

This time, however, something had changed. Stuck up with Blu Tack at various points on the wall behind the counter were hand-written notices. Some in two different coloured inks, to emphasise a word or phrase. The lettering was up-and-down and uneven in size. The messages were unexciting, like “for hygiene reasons, cosmetics are non-returnable” or “open 365 days a year”. I looked at the dapper pharmacist behind the counter and wondered what was going on behind that composed exterior. Was he cracking up – perhaps under the strain of being open every day of the year? There was no hint in his face or behaviour as he efficiently served each customer.

Why did he feel the need to mess up his pristine shop with these scrawled signs? I had no way of knowing and so, after feeling a little disappointed that he had let his professionalism slip, I thought no more about it. But I am now convinced that such ad hoc notices are the Sugar Test with which one may accurately gauge the sanity of those in charge. The more notices, the more paranoid or unhinged.

All too soon it was time to fly back to England. And there, in the airport arrivals, as I and a plane load of passengers obediently shuffled in a snake towards passport control, I was reminded of the pharmacy once more. “No photography in this area”, “No use of mobile phones”, “Passengers without a valid passport may be liable to imprisonment”, “Wait behind line until called forward”, “Stand to front of desk”.

This last admonishment was actually explained to us by the Immigration Officer as my partner strayed to the side of his desk. “The law in front of the desk is different from the law there” he said, as he insisted she moved a metre diagonally back. I fleetingly wondered if we had not in fact landed at Manchester, but had fallen down a rabbit hole …