You can travel to the UK, but having a successful landing interview may present problems.
You're in breach on your Schengen, and this would need to be disclosed to the IO because it is a material change in circumstances (Paragraph 321 (ii) and (iii)). If you chose to disclose it, you will need to think up a good explanation in order to convince the IO that you are not a risk.
If you chose NOT to disclose, and the IO discovers it on his own, you will then be in trouble and getting bounced is almost a certainty. Because you did not disclose material facts, your transcript MAY contain a reference to Paragraph 320 of the rules. It's a bad position to be in because your credibility has been blown.
Alternatively, if you chose NOT to disclose and the IO does not notice it, you're good to go. The next time you apply for a visitor's visa, however, will be difficult if they spot it when the consulate inspects your passport. If they spot it, you'll be logged as an illegal entrant.
The IO is entitled to bounce someone under Paragraphs 10 and 10B of the rules. If Paragraph 320 (7b)(d) is used as the grounds, then forget visiting the UK for a while.
If your landing interview is not successful, you'll be bounced (i.e., turned around, refused entry, etc)
Adding: when you applied for a UK entry clearance, you signed an agreement to notify them of any changes in your circumstances.