How to write in the SOP that I need funding?
Disclaimer: Your post lacks some important details (field, university, and your nationality) so I am going to make a few assumptions. In the past, I also applied to PhDs in the UK, so I will give you an answer based strictly on my experience and what I was told by my prospective supervisor at that time. 

I am going to assume that you do not have British or European nationality, since most British and EEA PhDs are funded by the relevant funding bodies (ESPRC, STFC, and others depending on field). Your options as a person without UK or EEA nationality are unfortunately very limited where funding is concerned. You are restricted mostly to funding from the supervisor directly (which you mentioned that yours do not have), a scholarship from the university (e.g. Rhodes), or incredibly competitive country-based scholarships (e.g. Wellcome Trust, Fullbright and so on). Unfortunately, international students (PhD and undergrad alike) are considered a giant source of income for universities, and there are very few scholarships available for people in this situation. 

Do you know how much your tuition will cost? Are you looking for funding for this plus a living stipend during the course of your PhD, or are you able to support your own living expenses? 

From my experience, and what I was told by my prospective supervisors at the time, the SOP is not supposed to mention funding. I personally would not include this in my application at all. However I would bring it up with the supervisor and with the relevant department. If your supervisor specifically advised you to mention funding in your SOP, then don't listen to what I'm telling you. When I went through the PhD application process in the UK, every university had a question about my nationality and how I'd be paying my tuition. Most had a radio button to indicate that you would need a scholarship or bursary. It is my personal suspicion that many universities use this query to rule out those of us not rich enough to fund our own PhDs or who can't take out loans for them.

If you wish to know more about the funding which is available to students of other nationalities, I can tell you what I know. It just isn't your specific question, so I won't type that all out straight away. I also answered this extensively in another question (which you can see here).

As far as what you have written, I agree with the commentor on your main question; your sentence comes across as resentful or even antagonistic depending on how it is read. I also agree with the second comment to your original question posted by Nate Eldrege; what you are alleging in the sentence is also factually incorrect (and maybe it is correct in your field, but it is subjective and unnecessary here), which will come across poorly. If you truly do want to mention your situation in your SOP, I would do so as neutrally and factually as possible. Something more like:


  [Briefly summary who is the professor and his work] My desire is to be able to work with him, and it is my main motivation to apply to University X. I have contacted him and he is very interesting to work with me. However, Professor X, while interested in taking me on as a student, is unable to fund me at this time. Because of this, I will be applying in tandem for any funding available to students in my situation.


This lets them know that a) you have researched your options and your obligations as far as tuition/living expenses go, b) you have made good contact with Professor X, and c) you are exhibiting independence with respect to funding your work.

I can say that point c is very important, because being funded as a foreign person in the UK is very rare and you have to do a LOT of work and compete with many, many people to receive it.

All of this being said, the university may well offer you a place to study your PhD (it happened to me) but without funding. If you can't self-fund, you just have to decline the acceptance. It is a lot easier for an international student to get an offer of a PhD place in the UK than it is to get funded for it.