In the stock market, Clyde's shares closed 2p lower at 116.5p as investors started to worry that Gulf Canada might walk away rather than stump up a final bid that would satisfy Clyde's large shareholders.
One leading shareholder, who described the figures as "quite punchy", said he would be happy for Gulf to withdraw its existing 105p bid. He thought Clyde's shares would hold their ground around the current price.
Gulf Canada, which last week employed a team of industry consultants to analyse Clyde's figures, dismissed its target's final defence. JP Bryan, chief executive, said: "The valuation put forward by Clyde's board is not credible. Simply plucking values out of the air will not persuade either Gulf or other shareholders."
Malcolm Gourlay, chairman of Clyde, said the company had "never been in better shape. The results of our strategy have paid off and all the pointers to our future performance are very positive". He added: "Now it is crystal clear quite how seriously Gulf Canada has undervalued Clyde's potential under its existing management team."
In the 12 months to December, Clyde reported a 93 per cent rise in operating profit to pounds 65.2m. Commercial reserves rose 38 per cent to 133.8 million barrels of oil equivalent and cash flow after tax and interest was 37 per cent stronger at pounds 113.5m.
As expected, Clyde ended its defence with an asset valuation commissioned from industry consultant ERC that put a value on the company's existing assets of between 120p and 144p depending on oil price assumptions. Clyde said most UK exploration companies were trading at an average 35 per cent premium to net assets.
Gulf has one week in which to return with a higher bid or announce its existing offer final.