Pilots represented by Balpa voted by 93% to walk out on 9, 10 and 27 September after efforts to agree terms on a new pay deal failed.

“Over several days of Acas talks, Balpa put forward a number of packages that we believe would have resolved this dispute without a strike, and which we could have recommended to our members for acceptance prior to strike action,” Balpa said in a statement.

“BA did not accept any of these packages, and it is clear following discussions with members over the past few days that BA’s most recent offer will not gain the support of anywhere near a majority of its pilots.”

The union said that “with no prospect of any further meaningful talks, we have no choice but to call this action" claiming that three days of strike action would cost BA “in the region of £120 million”.

“In what is BA’s centenary year, this will be the very first time its pilots will go on strike. They do so as a last resort and with enormous frustration at the way the business is now being run,” Balpa added.

BA branded the industrial action “unjustifiable”, adding how it believed Balpa to be “destroying the travel plans of tens of thousands of our customers”.

“We are extremely sorry that after many months of negotiations, based on a very fair offer, Balpa has decided on this reckless course of action,” the carrier said in a statement.

As a result of the strikes, BA said it was “likely many of our customers will not be able to travel” with refunds and rebooking being offered for customers on cancelled services.

BA said it was exploring options to supplement its fleet by wet-leasing and was working with partner airlines to schedule larger aircraft to fly more passengers on impacted routes.

Flights with BA CityFlyer, Sun-Air and Comair are unaffected.

“Our proposed deal of 11.5% over three years is very fair and well above the UK’s current rate of inflation, and by contrast to Balpa, has been accepted by the members of the Unite and GMB trade unions, which represent nearly 90% of all British Airways colleagues including engineers, cabin crew and ground staff. In addition to basic pay, pilots also receive annual pay increments and regular flying allowances,” BA continued.

“We continue to pursue every avenue to find a solution to avoid industrial action and protect our customers’ travel plans.”