Investigators are trying to establish whether a gem said to be worth £11m was used to inflate the assets of Wrekin Construction, which has gone into receivership.

The mysterious ruby — called the Star of Zanzibar — was bought by the Shropshire-based firm. On paper, it is the most expensive ruby on record.

But officials from Ernst & Young, the administrators handling Wrekin’s affairs, are understood to be trying to establish why the gem was bought or whether it exists at all.

Wrekin reported in its accounts for 2007 that it had bought the Star of Zanzibar from Tamar Group, one of its shareholders, for a 'fair value' of £11m. It paid in interest-bearing preference shares.

The purchase transformed the appearance of Wrekin’s balance sheet, helping to turn an £8m liability in March 2007 to net assets of £6m by the end of that year.

At the time that appeared to be enough to save the company from liquidation.

Sunday Telegraph