Norwegian closed its UK long-haul operation, known as NAR UK, on 14 January, making around 1,100 staff redundant.

Staff were told by liquidators KPMG they will not be paid their salaries or any other monies owed but must now claim part of pay arrears from the UK government - despite the airline continuing to operate as a Norway-based entity.

It then emerged around £10.5 million “is receivable” from NAS Invest, another part of the Norwegian group. Another £749,000 is owed from Spanish and US subsidiaries.

Pilots’ union Balpa said: “In our view, this money should be made available to help pay what is owed to pilots and other staff – including salary arrears, unpaid pension contributions, unpaid notice and in some case unpaid medical bills.”

In a letter to Norwegian, Balpa said it was “shocked” Norwegian director Dan Flynn “could not identify” the company owing the £10.5 million when asked in a conference call.

Balpa said: “We would like to ask once more who NAS Invest is? This is a large sum of money which our members could benefit from.”

The liquidator’s report estimates an initial £3.3 million will be available for preferential creditors.

However, the report said: “Employees should note that their wages and holiday pay will be met by the Redundancy Payments Service (“RPS”) up to the capped statutory limit of £538 per week, and any balance owed would fall as a preferential claim in the liquidation (up to the preferential limits), however, as there are likely to be no assets, there is unlikely to be any dividend to be paid out to preferential creditors.”

Norwegian has been asked to comment.