Presenter Denise Van Outen marking British Airways’ 40th anniversary by wearing a vintage air hostess uniform from 1974. Photo: Nick Morrish/ British Airways/PA Wire

British Airways is celebrating the 40th anniversary of its formation – a four-decade history that has seen a loss-making organisation transformed into one of the world’s leading airlines.

In the years leading up to April 1, 1974, BA had been, effectively, two companies – British Overseas Airways Corporation (BOAC) and its European division British European Airways (BEA).

The operation was state-owned at a time when open skies policies and the subsequent revolution in air travel through low-cost carriers were many years away.

Neither BOAC nor BEA enjoyed great reputations. Indeed,

BOAC acquired the unfortunate nickname ‘Better on a camel’. In its early days, BA was generally seen to be an over-staffed airline operating many loss-making routes.

Transformation came in the shape of ebullient chairman Lord King.

Cunning and ruthless, with a flair for the aviation business, King joined BA in 1981 and turned massive losses into huge profits by the time the airline was privatised in 1987.

He cut staff numbers considerably – something that most of the successor bosses at BA have done.

With BA chief executive Colin – later Lord – Marshall, King formed a highly-effective double act. Marshall was the rapier, always reasonable and soft spoken, while King was the bludgeon, often rude and belligerent.

Both had to survive a tricky period for the airline in the early 1990s when BA came a cropper in the so-called ‘dirty tricks’ case with Richard Branson’s airline Virgin Atlantic.

A long, protracted affair ended with BA having to pay Sir Richard large damages and having to fork out for punitive legal costs.

For many, one of the saddest things was the axing of Concorde flights

In more recent years, BA has survived the impact of the no-frills carriers and much consolidation and competition from world carriers.

For many, one of the saddest things was the axing of Concorde flights in 2003. But the supersonic service – although iconic – was not a money spinner and environmentalists pointed to the noise and the pollution.

After years of pressing for a terminal of its own at Heathrow, BA was able to move into the new Terminal 5 in March 2008. After a disastrous opening day, the terminal has proved a huge success.

The big change to BA in recent times was the merger with Spanish carrier Iberia in 2011 to form International Airlines Group (IAG).

This was masterminded by BA’s chief executive, Irishman Willie Walsh who now heads IAG. More of the King school than the Marshall one, Mr Walsh’s tenure saw a damaging cabin staff dispute and further slimming-down-staff measures.

The Iberia merger has been far from smooth but BA’s position as a leading world carrier is assured.