Get creative with ports of entry. Consider any and all of the UK's airports. Fly into London Gatwick or even Exeter as a cheap alternative to Heathrow. Let travel agents, online search engines and anyone helping you know this.
Research and contact ticket consolidators and bucket shops who can find discount deals not available to the public through retail channels. Consolidators buy blocks of unsold or difficult-to-sell airline tickets at a discount from airlines who want their seats full. Bucket shops buy what consolidators are having trouble selling, sometimes for even less. Consolidators and bucket shops then turn around and sell them to the public. Be flexible on airlines, routes, dates and even ports of entry to get the cheapest fare.
Review websites of airlines flying to the United Kingdom. Many airlines offer special fair promotions and discounts through their own websites that they don't sell by phone or via travel agents.
Search flights using online travel sites. Most of the major travel sites have features where you can elect to be flexible with dates in order to see the best fares. These types of searches can sometimes produce some hidden gems. A night flight on a Wednesday can be cheaper that the morning flight on Thursday or flying into Gatwick instead of Heathrow can save you $100.
Speak with a travel agent who specializes in charter flights. During peak travel seasons--especially in summer--private aircraft operators often run their planes like airline flights. Not every travel agent deals with the charter companies. Do some research in your local newspaper's travel section or online to find the right agency. Charter flights can save you hundreds of dollars.
Check with both airline websites and ticket consolidators last minute if you haven't had success with early planning. Sometimes airlines either drop fares for last-minute online specials or sell seats off to consolidators at significant discounts just to make money off the seats that aren't selling.
