Nearly £21 million is owed to more than 1,000 creditors of collapsed Shifnal firm Wrekin Construction and the value of its mysterious ruby gemstone may never be known.

Administrators have revealed the Gem of Tanzania, the ruby reportedly worth £11 million, is so unique that experts have been unable to put a proper value on it.

The details, which also show that Wrekin owed £3.4 million in VAT, were revealed in a 47 page report on the Wrekin Group, and its subsidiary Wrekin Construction, by Ernst & Young in advance of a meeting of creditors next month.

The report says: “Upon appointment, we were advised by the directors that the gem was held by an agent of David Unwin, a director of Wrekin Group, located in Saudi Arabia.

“Following numerous conversations, arrangements were made with David Unwin for the item to be returned to Wrekin Construction.”

The report confirms that the 2kg rock is natural corundum, otherwise known as a ruby, which is opaque and not of a good enough quality to be faceted.

It also confirms the valuation of £11 million was a “forged document”.

The report adds: “At this time, it is not possible to place a value on the uncut stone given its unique nature and consequent absence of any comparable market data upon which to base any estimate.”

The report lists more than 1,000 businesses and individuals owed money by the company, chaired by David Unwin, when it went into administration on March 10, and also gives reasons for why the company collapsed, with the immediate loss of 410 jobs.

It says: “Further redundanices were made throughout the initial weeks of the administration. As of April 27, 2009, nine employees remain with Wrekin Construction to assist with the realisation of the remaining plant and machinery.”

Ernst & Young say work still needed to complete the administration of Wrekin includes collecting debts owed to the company, pursuing any legal action required to recover the assets of the company and agreeing claims and paying the company’s creditors.

A meeting of creditors will be held at at the Holiday Inn in Telford on May 13.

By Business Editor Amy Bould