Administrators of collapsed contractor Buckingham have said the amount owed to its supply chain has gone up to more than £300m.

The firm, which had been targeting a £700m turnover in 2023, collapsed last September with nearly 500 jobs lost.

The following month, Grant Thornton initially said the amount owed to the supply chain was just over £108m but in the spring said this had climbed to £256m.

Buckingham was set up in 1987 and has been targeting a £700m turnover last year

Now, in its latest update filed at Companies House last week, the administrator said this had risen to £302m with claims totalling £266m from 682 creditors.

It added: “Claims are yet to be received from 709 creditors with a reported value of £36m, bringing the total expected unsecured claims to £302.2m.

“We have been notified of several claim or protective awards brought by former employees. The tribunals are currently in progress and may result in further unsecured claims in the estate.”

The report said “the prospect of a return to the unsecured creditors in unclear” but admitted: “We do not consider it likely that we will have sufficient funds to make a distribution to unsecured creditors and therefore intend to exit the administration and move to dissolution.”

The amount owed to HMRC, listed as a secondary preferential creditor, is unchanged at £34m, more than £31m of which is for unpaid VAT.

Grant Thornton has told the taxman it expects to make a payment but added it did not know how much at this stage.

At the time of its collapse Buckingham, which in its last set of accounts had a turnover of £665m in the year to December 2021, had just £4.98m in its current account with HSBC.