Tomorrow I'm travelling from Brussels to London via Eurostar. The problem is that I lost the electronic chip in my passport yesterday. Could they reject me at the check-in? Please help me I've been worrying about this all day...

You would be better off contacting your consulate with a question like that. They made need to issue you with an emergency replacement passport.

If you're British or Belgian (or any other EU nationality): you certainly can't be rejected at UK immigation. You have an absolute right to travel, and a chipfree passport still proves who you are. Since UK immigration is on Belgian territory before you embark, the carriers' usual problem (an illegal potential immigrant is only found out once they're in Britain, so the carrier gets fined) doesn't apply. So Eurostar SHOULDN'T refuse you check in. But they ARE taking a risk, so maybe not.

If you're non-European, the likelihood is that Eurostar will let you check in. Whether UK immigration will let you through is a whole nother story: would yours allow me through with a damaged passport?. I'd see if my embassy was still functioning if that were the case

I'm Belgian, so I hope to God they'll let me through. I really don't know what the chip serves for though, the only extra info it gives is my adress.

It can't hurt, though, to phone your passport office and see what emergency service they offer.

Her Majesty's Passport Inspectors might not necessarily be too impressed if you say "well, flanneruk said on Fodors it'd be OK"

If you are a Belgian national, then you don't need a passport, your ID card will do!

It's the chip in my ID Card that's gone missing...