Jewellery experts today poured scorn on reports collapsed Shropshire building firm Wrekin Construction was the owner of a ruby worth £11 million.

See also: Probe over firm’s finances

Company documents claim the ruby, known as The Gem of Tanzania, was bought from one of its shareholder businesses and the “fair value” was placed on the stone by the Institute of Gemmologico in Italy on August 31, 2007.

But today Loridana Prosperi, one of the Institute’s senior gemmologists in Milan, said: “That is impossible, because we were on holiday on August 31, 2007.”

And she claimed her company never assessed the price of gemstones, only the quality.

Auction house Christie’s also expressed doubt about the accuracy of Wrekin Construction’s claims, revealing the highest recorded price ever paid for a ruby on the open market was just £2.6 million, in 2006.

According to Ms Prosperi, an £11 million ruby would be equivalent to the world famous Black Prince, a jewel the size of a chicken’s egg which is embedded in the Queen’s crown.

Wrekin Construction, Lamledge Lane, Shifnal, went into administration earlier this week with multi-million pound debts and has since laid off more than 400 staff.

Jonathan Guthrie, enterprise editor at the Financial Times, said the firm’s 80 creditors were demanding answers about the details of the ruby contained in Wrekin’s 2007 accounts.

The ruby is said to have been bought by Wrekin Construction from its parent company Tamar Group, in return for the issue of 11 million shares, worth £1 each.

David Unwin, Tamar chairman, was confronted by reporters yesterday, but declined to comment.