Which? survey finds Essex location scores 84% among passengers, while three Heathrow terminals rate among worst

A £21m gamble to convert a sleepy runway on the Essex coast into London Southend appears to be paying off, after consumer group Which? rated it the top airport in Britain.

The survey gave Southend an average customer satisfaction score of 84%, as smaller airports far outperformed their larger rivals.

Three of Heathrow's four operational terminals rated among the worst, with fewer than half the passengers satisfied. The newest Terminal 5 outscored all large airports in the south-east.

London Luton, which changed hands this month to new Spanish owners, had the most dismal scores of all, with its security queues and general environment rating particularly badly.

The Stobart group – home of the trucking business of that name – bought Southend in 2008 with a view to building a new terminal, railway station and control tower.

After trimming a churchyard to lengthen the runway sufficiently for short-haul passenger jets, the airport officially reopened in March 2012, with easyJet as its major customer. The airline has now carried more than 1 million passengers from Southend to 14 destinations across Europe, recently linking the Essex resort to Venice and Berlin. More traditionally, holiday firms Thomson and First Choice operate package holiday flights from Southend to Mallorca.

An easyJet spokesperson said the findings matched its own research that showed Southend coming top in the UK for customer satisfaction levels. "It's very easy to reach from the new train station and very easy to get through – it tends to be a very positive experience."

The survey awarded Southend five stars for aspects including information and navigation, though an airport source suggested any passenger looking for the way through the small departures hall should simply "open their eyes".

Which? executive director, Richard Lloyd, said: "It is clear some of our major airports have some work to do if they are to keep more of their passengers satisfied."

Which? also surveyed pre-departure queues and found passengers who checked in online and used bag-drop desks were often waiting as long or longer than those who checked in at the airport.

Stansted airport consistently showed the longest waits for check-in and bag drop, and Ryanair customers checking in baggage faced the longest queueing time of any airline they surveyed.

• This article was amended on 19 August 2013 to change the spelling of Mallorca, from Majorca.