CIS Contractor goes bust

CIS Contractor goes bust.

Liquidator publishes list of creditors including £300,000 owed to HMRC. No monies available for unsecured creditors.

My client has been a subbie to the main contractor for 2 years. 20% deductions always taken.

Last 3 months my client wasn't paid; strung along with promises, refinancing, all be sorted soon, etc.

My subbie client is owed £10k gross. Is there a case for saying that £2k of this is owed to HMRC and £8k owed to my client.

If not why not. How could anyone ever establish the makeup of the HMRC Creditor of £300k?

Anyone come across a similar situation?

Thanks to any respondents.