JFK upgrade to PE Cost???

I am due on a flight from JFK to LHR soon and was wondering if anybody knows of the average(if such a thing exist's) cost of upgrading to PE at the airport???

That is if I dont get a free upgrade to UC! [:o)]

Thanks.

it varies greatly - if available at all on the day
The time of year and load are the main factors that dictate price I've heard it as cheap as a few hundred bucks and as expensive as what you'd expect to pay for a PE ticket! I'm sure frequent JFK ers will give you price guides!!

^ The loads have no effect on the price. The class of ticket you have dictates the upgrade price.

Of course this is only if they are seats available.

The day of departure upgrades are the same price everyday, but aren't disclosed.