You will not find any trouble to get a cheap airfare to London. In fact it depends upon on your travel dates, and what kind of facilities you want. If you are not finicky about flying Asian Airlines like Air India or Kuwait Air then these should be your first stops.

There are many Asian airlines fly through London and sell tickets through consolidators. Most Asian passengers use airlines of their countries to book home passages so the seats allotted on the US-London sector stay empty. You can get an inexpensive seat till London on these flights easily.

During the off season the London seats are even cheaper than ever. Particularly in the middle January to end March and November 1 to early December there are two peak periods when tickets are cheaper. Very few people travel during these months. In fact this is the best time to travel London during these months.

However the best way is to get an advance for your trip. In fact many airlines release their cheapest seats to travelers who book their tickets well in advance of the flight date. Even you can get slightly less discounted tickets if you get late for these tickets. These tickets are released from time to time by airlines. In addition to this you need to be alert and visit the airline sites frequently to get a lucky ticket.

If you will quote your price on Priceline.com, then some airline will be willing to sell a London ticket at that price. The disadvantage of this deal is that you will not get any refunds. If it does not suit you, you can take the flight also.

You should not forget the sites that send low fare alerts. Try to become a member of at least a couple of these sites. You never know when you may get a great offer.