It's emerged the Treasury's most senior civil servant offered to resign over a mistake in financing the airport runway extension, which has cost the Manx taxpayer more than ?2 million.

Chief Financial Officer Mark Shimmin told the Public Accounts Committee he took responsibility for failing to forward-buy Euros to fund the RESA scheme, before the value of the pound plummeted against the Euro.

He offered to stand down in January when the scale of the loss became clear, but Treasury Minister Allan Bell, persuaded him to stay.

The runway extension scheme, to be part funded in Euros, received Tynwald approval in April 2008.

But no one in Treasury ordered the purchase of Euros at the prevailing exchange rate, a blunder which has added ?2.2 million to the bill.

In Tynwald in February Mr Bell admitted mistakes had been made.

The Public Accounts Committee yesterday heard evidence from Allan Bell, Mark Shimmin, and Financial Controller Clive McGreal, who told the committee it had been a major oversight, the result of a breakdown in communication between different officers.

Mark Shimmin said he had been deeply concerned about the consequences and, after considering his position, tendered his resignation on January 19.

He was persuaded to stay, but told the committee if he lost the confidence of the Treasury minister or Tynwald members he would resign again.