Thanks for your reply.
If you cannot switch in to another visa category (ie. student or workers) then you will not be able to obtain a new legal immigration status. There is little point in making an application that you think may fail because they will want to know why you are switching and the issue of your relationship ending will be revealed. If revealed they will curtail your visa and ask you to leave.
You would then be an overstayer and this would probably prejudice any future application you choose to make.
You can remain here under your current visa until it expires as long as your ex-partner, or anyone else, does not disclose the break up to the UKBA. This may be your best option. Again though, you should not overstay for the reason aforementioned.
Again, leaving the country and making an application then would probably reveal that your relationship has ceased and complicate your return. There is also the problem of what visa to apply for if you do not qualify for one of the above.
I'm afraid there is no magic bullet for your situation, you are either eligible for one of the other visa categories or you are not. The key is to keep your ex-partner amicable and try to avoid her disclosing to the UKBA/Home Office that your relationship has finished.
If before your current visa expires you can accrue enough points for a workers visa, or arrangements to qualify for a student visa then this is something you should attempt to do. If you cannot do this or find someone with leave to remain to marry then your position will remain unchanged I regret to say.
Sorry it could not be better news.
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