Upvote:17
Transit visas are for entering a country where the only purpose – or, at least, the main purpose – is to connect to transport to a third country. Your purpose for visiting the UK is purely tourism: you want to spend a few hours visiting and then return to the country you came from. You can't do that on a transit visa: you need a Standard Visitor Visa.
Purely as a matter of opinion, there are millions of things to see in Schengen, and I wouldn't go to the expense and trouble of getting a visa for a few hours' touristing. Go to Paris, instead. Or stay in Amsterdam: there's plenty to see there, too.
Upvote:29
If you're making a day trip to the UK and then back to the place you arrived from, then you're not in transit, and a transit visa wouldn't do you any good.
You'd need a Standard Visitor Visa, which must be applied for in advance. The 8 days you have until you leave will probably not be enough for this application to be completed unless you pay for super-crash-priority service.
Thus, realistically, no, you can't go to the UK.