No trade body can coordinate a boycott of the airline and its sister brands Austrian, Swiss and Brussels Airlines, as it would be illegal under European law, but the Scottish Passenger Agents’ Association, which met with the carrier last week, spoke of the consequences of Lufthansa’s move to a direct channel.

SPAA vice-president and air convener Alan Glen warned: “Lufthansa could lose a lot of business.” He said the Scottish lobby was significant and that many were already selling away from the German group: “There are some fairly big players in terms of the TMC market and we have the Aberdeen oil and gas and the regional market in terms of connections. There are new carriers and other options.”

Advantage business travel director Ken McLeod added: “No matter what legal challenges and shouting there is, until they get less business through their door, Lufthansa won’t do anything. It’s down to the trade, corporates and consumers to decide whether they want to pay an extra €16.”

Lufthansa officially launched its direct-booking channel on Tuesday, with chief executive Jens Bischof saying he wanted “to work together with the travel agents and the global distribution systems to make the sale of air tickets more up to date, more inexpensive and more customer-minded”.

McLeod said the airline was doing the opposite of this. “You do have to question their sanity,” he added. Nothing was likely to change in the next few weeks, he said. “We are in the eye of the storm where we just have to sit and wait for the reaction.”

Agents are already reporting issues with Lufthansa’s systems, with the SPAA describing the new booking portal as “not fit for purpose”. Glen said a meeting with the carrier last week made him believe Lufthansa was aware of this. “I think they know it’s not ready,” he said.

McLeod added: “The current website will improve, but they don’t understand the processes involved in business travel agencies that are linked inexorably to the GDSs.”