I am based in the uk - please can you tell me what type of cleaning is the most profitable and why. Thank you in advance.

It's the one run the most professionally by a diligent, organized, intelligent, responsible person who knows what it means to be a business. There are no mistakes or excuses in the business dictionary. You prepare for all things that can go wrong, you write contracts that cover all that and more, and you learn how to estimate. Good estimation is key to any service company.
It worries me a bit that you are even asking this question. To think that there is a list of the most profitable types of cleaning companies is meaningless.

I puzzled I think it's a reasonable and intelligent question is soffit cleaning more profitable than an after builders clean? Are offices more profitable etc etc. which one despite good estimation is overall is more profitable ?

My answer still stands, but I'll rephrase it:
One person may make more cleaning soffits than a person cleaning construction sites. The soffit cleaner might buy out the person cleaning construction and make more than that person did.
There are countless tales of this happening. And many cases of businesses failing and being bought back by the original owner, who brings it back to profitability.
Pick the one you can afford to buy equipment for, and expand into all the other cleaning fields as you make each dollar. How about soffits, gutters, and power washing decks and siding to start? A compressor, some barrels, a ladder... you could offer to stain the decks when they are dry. You could replace rotten boards. And so on.

Maybe it's just me as I do not understand. I would like to start a cleaning company but not sure what to focus on I know nothing about soffit or cleaning anything other than my home but if I am to start something I wanted to do what was the most profitable. Lets say I can afford to buy equipment for all types of cleaning. I like your theory if I'm understanding it correctly but what I want to know is from scratch without someone putting their stamp on it or turning it around etc which is the most profitable from day one?

I'll keep trying.
Let's say you start with gutters. Not much to learn there.
Your ads are good. Your word of mouth referrals are good. You know how to quote, and don't try to add to them saying 'oh it was just an estimate.' You show up when you say, and do a thorough job, and don't leave muck and leaves debris all over the house and ground. You collect your payment and were clear about what costs are before the job and that payment was due on the spot. You are polite and cheerful.
The next gutter cleaner is none of those things. You make good money, he doesn't.
Get it now??
If you don't - then you aren't ready to be self-employed.

Thank you. Well I get that but you can't get away from the fact that on the face of it before starting in any sector one most be more profitable than the other, for example, I have since found out that a 4 bedroom after builders clean is more probable than cleaning a lived in five bedroom house. Do you get it now? So logic tells me that I should go for the after builders cleaning space - NOW that I've identified which is more profitable I can apply all of your lessons that you've taken the time to point out to me. I really was looking at grass roots level is cleaning air conditioning ducts more profitable than cleaning up blood spills, is carpet cleaning more profitable than industrial cleaning - obviously I don't mean these examples literally but just wanted to give you more of a flavour of what I have been trying to convey. Naturally your points are valid and obvious but surely if you have no particular love for a particular market and want to make money you would then go for the area that has the most profit THEN apply your theories! Your last example is obvious whether your doing gardening, cooking, etc etc. My point is I've chosen cleaning - BUT what should I clean WHAT is the most PROFITABLE.

By the way what is your background, what do you do? I myself am currently doing nothing and welcome your advice. Thanks again

I'm old and retired. I have had 36 jobs in my life, mostly in the building trades, doing office management and bookkeeping, job costing and estimating - and constantly figuring out ways to help the company make money, which includes not losing money. I really do know how a one man operation of any kind makes it or breaks it.

I 'get' a lot more than you can imagine. If you think your comparison of 'profit' of a builder's clean vs a house cleaning is a good one, be my guest. I've said all I'm going to say.

Start small. You aren't going to be hugely profitable in the beginning. You want to build up your customer base and always be looking for new customers by word-of-mouth and ads and a brochure and other marketing techniques. Thus, you need a good plan for doing that. After all, no matter what kind of cleaning you do, if you have no customers because you haven't done the correct kind of marketing and if you lose any you get because your customer service is poor, you won't make any money.

Choose one kind of cleaning to start with and do it well, as Joy said. My friend started just painting interiors. Over time, he added stripping wallpaper, putting up new wallpaper and borders. Then, when that worked out well and was profitable, he added painting or staining wooden porches and decks after he did any light repairs (reinforced steps and rails, etc.). Then, when he had money to spare, he bought power washing equipment and power-washed houses and garages. He will also do other light repairs. He always is working and is making tons of money. But he started small and did that well and progressed from there.

He doesn't get it no matter how many ways you say it.
He has no skills, no job, and just keeps thinking he has to FIND a quick answer that isn't there.
Some people can sell snowballs to Eskimos, and some can't.

And lots of money NOW!!