LOL - it's really your lucky day. A bit of a fare glitch involving IB fares operated by AA and BA from SFO, LAX, IAH, and more....if you're lucky you can book a ticket right now for right around $400 on a non-stop BA flight through iberia.com
follow that thread posted about houston flights - it's the same deal just a bit more expensive from SFO. This is how you get to LON/PAR for under 700 from the west coast. And don't expect to find anything cheaper anytime soon, most of these pricing errors have been from the east coast lately...