Can someone with a Turkish passport and a US greencard go to Heathrow Airport for a layover w/o a visa for UK? This might be a stupid question, but I don't know where to find this information. Thanks!

Alternativly just burn everything and you should get a council house and £20k a year in benefits lol..only kidding... If your not passing through customs it should be ok. Try a UK immigration or the Heathrow airport site...

What does "layover" mean? If you want to leave the airport, then you'll need a visa. If you're in transit (not leaving the airport), you won't need one. Your travel agent can confirm this.

http://www.ukvisas.gov.uk/servlet/Fr...=1006977149953

It looks like you are OK to transit (ie staying airside for the whole time) since you have a US Visa- but you could could call your agent, the UK Embassy or the UK Visa Service to confirm.