To put it into perspective, it's more than the cost of unlimited travel for one week across London if you live on the outskirts, or it's a week worth of groceries for two.
Now London's tax system is a little bit different in that the state waits for your employer to tell them how much you earned and how much tax you've already paid. The adjustment is then done for you. Nice.
Otherwise, if you're self-employed, you do your taxes yourself. That's when the fines come in.
But being self-employed could mean working as a casual cleaner or in some other low paid job, or writing down some equipment you bought for a business. Who is this fine really going to hurt and who is it going to help?
If you're wealthy and/or have an accountant then that's fine - you either pay the fine and it doesn't hurt at all, or you have an accountant you pay to get your tax return done on time. Great.
But otherwise, if you're too busy working all those hours for low pay, running your business, unwell or have some sort of issue in your life which means you're a little late putting in those figures in to HMRC, then you're fined 10 pounds a day.
It does add up and it hurts. It might even mean any return you had coming to you is cancelled out by paying more to the government.
It's a punitive measure that only punishes those that can't afford it. And for what? It might make the small percentage that's doing the wrong thing sit up and take notice, but ultimately it's a measure which means that those that can least afford it get hit.
It's a pattern that resembles the change that's been sweeping through Britain, demonstrating a punitive policy culture that's settling into this country from the top down, and it makes me rather nervous.
Discussions about cuts to housing benefits for young people, university fees sky-rocketing, high unemployment, equally high youth unemployment with numbers of young people in neither education nor training climbing for the first time in years. Private companies profiting off carers and the jobless in the same way vultures circle for the kill in a drought-starved land.
It's almost as if we are punishing the working poor and unemployed for no reason other than being underpaid or unemployed.
It wouldn't be so jaw droppingly shocking if the top tier - the 1% shall we say - were hurting as well. But they're not. Figures show that the rich have really done well out of the financial crisis and their quality of lives have been maintained or even improved.
Now with Barclays and the Libor scandal - we're seeing more of our nation's riches shoved into the pockets of bankers but no charges yet to punish those responsible. Rather odd given something criminal did take place.
Certainly the banking industry is yet to get a flogging equal to that which the poor or young and jobless are receiving.
What really makes me nervous is that all these policy decisions are being made by a Prime Minister who is really very wealthy himself.
Mr Cameron would never have had an issue with housing, given he inherits a rather nice structure. His only private sector job paid 90 thousand pounds a year and his wife's mother got it for him.
Regardless of political background - Tory or Labour - you want to know that the man or woman making the decisions for the so-called good of the economy really understands what he or she is doing. You want to know that Mr Cameron has lived the lives we've lived and gets it. (It's not unheard of, many of Australia's PM's have come from humble beginnings).
If Mr Cameron had experienced a hard-luck life and still thought the cuts were good for the country, maybe people would swallow it and carry on - in the great British way.
But this is a man who has had nothing but privilege. It frightens me that a man like that speaks for us all. A man who had it all rather easy, who was never, ever going to have his cheek near the rough edge of the road at any point in his life, no matter if he failed school, made the wrong career choice and saw his wages fall or accidentally got a woman pregnant.
That someone from that background tells us to trust him when he guts the paths to social equality and social mobility? I don't know, I'm finding it hard to swallow.
What I would expect is for business to be told in no uncertain terms - do not drive down wages, put more of your profit margin in your people so that quality of living is maintained, so that recruitment agencies aren't tempted to hire people who will work for much less (to the detriment of those people and the rest of us whose wages they undercut). So that we can afford the rent or the mortgage and so people don't have to rely on benefits.
Start employing and training young people and pay them a decent, living wage so that they don't need to subsidise their income with a housing benefit.
In other words, don't expect a government handout for your business just so you can make a profit while underpaying your workers - Wallmart style.
If you ask for the business (and banking!) sector to help share the load, rather than just cut, cut, cut government spending, maybe then I'd be happier about what was going on.
I'll tell you what - how about in return for Libor - a promise from Barclays to give 25 per cent of young unemployed or underemployed people from poor backgrounds traineeships with great first year pay?
Maybe then I wouldn't cringe as transport costs rival the mortgage repayments, as I struggle to get to work and as I lay down after a 14 hour day, just as exhausted as David Cameron, but no where near as filthy rich.
