On the 57th day of industrial action so far this year by some British Airways cabin crew, the airline’s parent company reported strong half-year figures. IAG’s operating profits before exceptional items rose 37 per cent to €973m (£870m) for the first six months of 2017.

The group also includes Aer Lingus, Iberia, Vueling and Level – the new low-cost, long-haul venture that began flying in June from Barcelona to Los Angeles, Oakland, Buenos Aires and Punta Cana in the Dominican Republic.

The improvement was driven by a 4.6 per cent increase in passenger numbers and a “load factor” improvement from 80 to 81 per cent.

IAG said: “Our largest markets, North America and Europe, also performed well and British Airways saw strength in its corporate bookings.”

British Airways was by far the biggest contributor to profitability, accounting for €741m. That represents more than £30 per passenger carried between January and June.

The long and bitter dispute involving Mixed Fleet cabin crew belonging to the Unite union at Heathrow was not mentioned in the results. The present stoppages are due to end on 15 August. But cancellations have so far been limited, with Qatar Airways lending planes and crews to BA; the carrier, which owns one-fifth of IAG, is operating about 30 flights a day.

Unite’s national officer Oliver Richardson said: “It’s time British Airways started talking about resolving this dispute which will further tarnish its brand.”

Iberia grew in Spain in Jerez, Balearics and Canaries, Aer Lingus increased its transatlantic capacity and Vueling grew in Spain – though the budget airline lost €6m.

Willie Walsh, the chief executive of British Airways, said Level was performing “well ahead of our expectations”.

“We’ve ordered three additional aircraft and are considering other European bases for the operation,” he added.