Can I enter England as a tourist, then my student visa will start two months later? [closed]

In May 2017 my son received a Tier 2 visa with which he moved to the UK in June and undertook multi-year employment in Cambridge. He applied for the visa months before, and his passport was returned to him with a new document inside (not the visa, just an information page) which disclosed the visa's start date; other documents indicated he should enter the UK “not more than 14 days before” the start date of his visa. After entry to the UK, he had to go to the PO in Cambridge to retrieve his biometric residence permit.

I don't know if your "days before" number is the same as his. Whatever it is, you must enter the UK after that point. Enter does not mean already be there, it does mean pass through the UK border into the UK.

Thus, I agree with @Hanky Panky: at or after your "days before" date, leave the UK by going to France, or to Ireland (not Northern Ireland, which is the UK), spend the night, and return to the UK anew.

On a Tier 4 (General Student) visa, if your course lasts 6 months or less, you can arrive in (i.e. enter, as the previous answer stated) the U.K. up to 1 week before; if it lasts more than 6 months, up to 1 month before. You’ll have to collect your biometric residence permit within 10 days of when you said you’d arrive in the UK (even if you actually arrive at a later date). https://www.gov.uk/tier-4-general-visa