Travel Corporation owner Apollo beat fellow private equity investor Castlelake in the race to acquire easyJet, agreeing a £5.7 billion deal earlier this month for the carrier, which celebrated its 30th anniversary last year.

However, the Prospect union has warned Apollo's commitments on employment, "while welcome", are limited to 12 months and are expressed as "intentions rather than binding undertakings".

"Prospect is calling for stronger and longer-term commitments to employment security, protection for collective bargaining arrangements and meaningful engagement with recognised trade unions throughout the period of ownership," it said.

Earlier this month, the Unite union said Apollo's "broad statements" about working with easyJet's employees "needed to be translated into reality". "Its growth strategy must translate into well-paid, unionised jobs and existing roles must be protected," said general secretary Sharon Graham.

Prospect has urged Apollo to provide easyJet employees with more transparency about its long-term strategy for the airline, the impact of how the proposed deal is financed, and how decisions affecting jobs, operations and terms and conditions are made in future.

"Prospect is calling for stronger and longer-term commitments to employment security, protection for collective bargaining arrangements and meaningful engagement with recognised trade unions throughout the period of ownership," it said.

It also cautioned Apollo against breaking up easyJet and selling it off. "Government and regulators should be seeking firm commitments from Apollo that they intend to build on easyJet’s successful business model."

In addition, Prospect is also seeking assurances from Apollo that existing collective bargaining arrangements will be protected, that the progress achieved through partnership working will not be undermined, and that employees will continue to benefit from further improvements in their pay, terms and conditions in the future.

"Prospect also believes employees and their recognised trade unions should be fully consulted on any significant organisational, operational or structural changes arising from the acquisition," it continued. "The long-term success of easyJet will depend upon retaining the trust, expertise and commitment of the workforce whose skills and professionalism have helped build the airline’s reputation and success."

Unite, meanwhile, which represents thousands of easyJet employees, including cabin crew, said it was engaging legal counsel to scrutinise Apollo's proposals for easyJet.

Regional Coordinating Officer Lindsey Olliver said: “Unite will ensure employees’ terms and conditions, as well as collective bargaining, are protected in accordance with the relevant legislation and agreements.

“However, the true strength of our members lies in their industrial power. We look forward to working with Apollo to ensure those protections remain in place going forward.”