Spying has always gone on, however, in the UK there is a lot of it. WW1, WW2 and the Cold War was all about spying. Considerable infrastructure was built to support this, culminating in 'Five Eyes'.
Furthermore, the former empire was built so that all of the telegraph and telephone lines went to London. If you wanted to make a call from one African colony to the next, London would be in on the man in the middle.
As well as this vast international capability, there is also the domestic front. During the Miners Strike in the 1980s the secret services were tasked with spying, notably on the leader of the miners, Arthur Scargill. Allegedly he used to pick up the phone and just give them a few words, either to misguide them or to tease them.
This spying continued with Northern Ireland being a 'training ground' during 'The Troubles'. There was also considerable opposition to cruise missiles in the UK during the Thatcher years and all of the people active in the Campaign for Nuclear Disarmament were under surveillance. This was not the end of it though. Eco-activism was also of interest along with a few high profile problem people.
As well as the secret services, there is also Scotland Yard. They infiltrate every anti-government single issue pressure group as a matter of course, placing people in deep cover. Two Guardian Journalists brought this to light in 2012 or so.
Then, on top of that, there are the capabilities of the big companies such as British Aerospace. They have their spies too.
Hence, on the domestic front, surveillance is vital to cut anyone down to size if they might challenge the establishment at a later date. Everything just gets nipped in the bud.
The 'Special Relationship' is the spying arrangement at the heart of 'Five Eyes'. In the USA, surveillance of the population is not allowed, so the workaround is to get the Brits to do it for them. This is how it works and has been working for decades.
If the UK secret services want to spy on someone in the UK then they will have the manpower to do it without getting caught. They will be able to get school reports, attendance at political demonstrations and much else regarding a person of interest.
There is nothing new that I have said here, Snowden and The Guardian brought all of this to light, in broad strokes. Both HUMINT and SIGINT is world leading. Compare with the USA where they have the dragnet but are not so capable when it comes to the HUMINT needed for monitoring a small group of individuals such as the leadership of a trade union.
It is for these reasons that spying has to be made easy for them, for instance by banning Huawei 5g routers on the pretence that China is using Huawei backdoors to spy on the UK. The problem was not that, it was different. With the likes of Cisco et al, the secret services can specify their own back doors, however, that is not so easy with Chinese owned companies.
There is much in the way of law that has gone along with this, for example the Criminal Justice Act of 1994 and the Terrorism Act 2000. The latter was definitely to target eco-activists, not anyone else. At the time there were eco-activist groups such as Reclaim The Streets that organised things such as rioting in the City of London with no identifiable leaders. They also did not book their protests with the police or organise security for the day, hence they needed to terminated.
9/11 brought new challenges and that brings us on to where we are today. I personally do not think this digital ID is a big deal. Any British citizen can already be easily identified even if they don't know their National Insurance number, and even if they have no photo ID in the form of a passport or a driving license. Name, date of birth and hospital of birth are the three bits of information needed. As well as the police, the NHS can work with that. As for employers and their needs to hire only people legally permitted to work in the UK, this is just for due diligence reasons from their part. If you speak with an accent that can only be British then you can meet the employer's checkbox requirements easily, with no photo ID. Just a bank statement should do.
So, where is this coming from? What plausible reason could there be for a fresh attempt at identity cards, for the umpteenth time?
Brexit...
As you know, Brexit happened and it was ugly. Due to the way that 'The Troubles' ended with the Good Friday Agreement, the border between Northern Ireland and Ireland (The Irish Republic is just 'Ireland', not any other name) has to be kept open.
What this means is that the EU is not a complete fortress, there is this imaginary border in the Irish Sea that can't be closed.
Immigration post-Brexit
A major selling point of Brexit was an end to immigration. However, due to the open border with Ireland, immigration has become a problem to the authorities, not least because working class people despise losing their jobs or getting paid less because there is a constant stream of people that will undercut them in the employment market.
What happens is that some country ends up being regime changed, as per the goals of The War Against Terror. Syria was particularly notable for the refugee situation. However, there is also Afghanistan, Iraq and everything in between up until Ukraine. What happens is very sad. People walk, hitch or smuggle themselves into Europe to arrive in one country such as Greece. Here they are looked after but they are unable to work or escape the refugee camps to buy a house, start a family and all those good things.
So they escape the cage of the EU country they first entered to try somewhere else. Maybe they get to Germany. However, in Germany, they will be asked where they came from, for example Greece, and get sent back to Greece. Maybe they try another EU country, to get sent back again. And so it goes, until someone advises them to go to Ireland, where they can walk over the border to the UK, as in Northern Ireland.
Since the UK is not in the EU, they get a fresh start at claiming asylum. This gets granted and the local authority is then likely to put them up in temporary accommodation.
Next they get 'dispersed'. What this means is that they get sent to another British town or city. Here they get temporary accommodation and a ridiculously small amount of money to live on. This money does not meet their basic needs. The asylum process leads to refugee status, which is not citizenship, however, they are permitted to work, legally. At a guess it takes two years to get to this second hoop. To get past refugee status takes even longer, if successful.
During this time the asylum seeker is not allowed their passport, the government keeps that. They can get a travel permit, however, if they return to their home country then they get banned and are not allowed back.
So that is the general process. To say immigration is out of control is an understatement to some and 'fascist' to others. It is a topic best not talked about, and the practicalities of it are not well understood. A boat crossing the English Channel full of asylum seekers are going to make the headlines of the gutter press, but this Brexit loophole situation is not something that the journalists appreciate fully, particularly if they voted for Brexit, then they are just not wanting to know.
Plausibly, the compulsory digital ID checks for work can be used to make the UK unattractive to asylum seekers that know the deal in the EU.
Currently the biggest threat to the main political parties is Farage and his Reform party. In recent polls, Reform (or whatever they are called) would sweep the board, taking seats from both the Conservatives and Labour. Due to how it works with no proportional representation, the exact outcome of this does not necessarily mean Reform would have a majority, however, it would be the end of the Conservative Party.
Hence, compulsory digital IDs would provide convenience for everyone, when dealing with the government, whilst giving the spies the primary keys they always wanted. However, for reasons of holding on to power, due to the threat of the Reform Party, there may be extra urgency.