MPs have labelled British Airways “a national disgrace” for trying to slash its staff terms and conditions during the coronavirus crisis.

In a scathing report, the Commons transport select committee accused BA of making “a calculated attempt to take advantage of the pandemic” through moves that could lead to up to 12,000 staff being laid off and the remaining 30,000 put on inferior contracts.

Although the report said some redundancies at BA and other airlines might be inevitable, it condemned the flagcarrier, which has been granted a £300m Bank of England loan and received £35m a month to furlough thousands of employees.

In conclusion, MPs said: “The behaviour of British Airways and its parent company towards its employees is a national disgrace. It falls well below the standards we would expect from any employer, especially in light of the scale of taxpayer subsidy, at this time of national crisis.”

BA issued formal notice to unions at the end of April of its plans to lay off staff and reduce terms and conditions. The 45-day minimum period for consultation will pass on Monday, although immediate redundancies are not expected.

The transport committee chair, Huw Merriman, said: “The impact of coronavirus may sadly mean that the loss of some jobs in the aviation sector is justified. The behaviour of British Airways and its parent company, IAG, is not.”

He said MPs would continue to bring pressure to alter BA’s plans, including potentially asking if its airport slots – it occupies almost half of takeoff and landing slots at Heathrow, Britain’s biggest airport – could be reviewed on competition grounds.

He added: “This wanton destruction of a loyal workforce cannot appear to go without sanction – by government, parliamentarians or paying passengers who may choose differently in future.”

BA said the report was “fuelled by impassioned messages” rather than the facts, and said: “The government has no plans to help the sector restart and recover, as evidenced by the introduction of the 14-day quarantine regulation. We find ourselves in the deepest crisis ever faced by the airline industry. A crisis not of our making but one which we must address.

“We will do everything in our power to ensure that British Airways can survive and sustain the maximum number of jobs consistent with the new reality of a changed airline industry in a severely weakened global economy.”

Virgin Atlantic, easyJet and other airlines are expecting to shed a similar proportion of their workforce, but BA’s proposals to force through inferior contracts on staff follow previous attempts, and ensuing industrial disputes, before the pandemic.

The report acknowledged the depth of the crisis facing aviation, and said helping the sector’s recovery from a 97% drop in passenger flights and the loss of £20bn in revenue in the UK should be a priority for government. It criticised ministers for failing to act sooner, saying that at four months into the crisis “the strategy should be more developed” and urged it to set out plans as soon as possible.

Meanwhile, it said the quarantine measures introduced last Monday would damage the recovery, and urged it to abandon the policy on review in favour of “a more flexible and risk-based approach to border control”. BA, easyJet and Ryanair have launched a high court action to overturn rules forcing passengers arriving from abroad to self-isolate for 14 days.

MPs also called for a temporary suspension of air passenger duty and business rates payments to help the sector recover.

The Unite union, which represents thousands of aviation workers, said the report was “an immediate wake-up call to the government”.

The union’s assistant general secretary, Diana Holland, said: “The chancellor first promised support for aviation in March and three months later that still has not materialised. The aviation industry must also respect the report’s findings and stop prematurely making workers redundant.”

Responding to the report, a government spokesperson said: “We recognise that this will be a very distressing time for all employees in the aviation industry and their families. We encourage businesses to respect the spirit of measures such as the job retention scheme.However, we stand ready to support those who may still lose their jobs.

“We continue to work at speed to help protect the long-term future of the sector. However, we will always put public health first, and we must not risk an extremely damaging second wave of the virus.”