There are some good business class deals out of London to New York for the Christmas and New Year period.
British Airways currently has a worldwide sale on. Club Class flights for London to New York JFK can be found from £1,322 (ex- Gatwick) and £1,329 (ex- Heathrow). These can be booked by 23rd September for travel between 16th December 2008 and 5th January 2009.
Virgin Atlantic have almost the same deal going – Upper Class from £1,332 from London Heathrow to New York JFK and Newark. Same travel dates as BA, also bookable by 23rd September.
Alternatively, Air France / Delta have business class prices at under £1,300 for London – NYC. We also found a £1,123 price on an Expedia special fare.
Icelandair fly London to NYC (via Reykjavik KEF) from around £1,170 in business class.