Rather than transferring planes in the larger and more congested English airports, like Heathrow and Gatwick, many travelers are going through the smaller Manchester Airport. To get more detailed information about Manchester Airport, you can go to Flyertalk. Many experienced travelers share their expertise and advice there.
If you are flying abroad and usually transfer in London, give the Manchester Airport some consideration. You might be surprised by how quick it is to go through customs and how easy it is to negotiate through the airport. Check with Flyertalk for more details.