Shares in Tullow Oil, the international explorer with headquarters in Dublin, slumped 6.25 per cent per cent in London yesterday after the company announced it was abandoning an oil well in Gabon.

The well, off the west African coast, is being abandoned following test drilling that showed "no significant quantity" of recoverable reserves.

Its Irish share price also fell, by 7.14 per cent.

Tullow did its best to shrug off the share dip, insisting it had high hopes for two gas-rich blocks it has acquired off the Dutch coast.

The company has bought the remaining interest in the field from Chevron Texaco for £19.43 million (€29 million).

The gas blocks, in the southern region of the North Sea, contain a "fizzy' area" - one that is rich in untapped gas.

With Britain in particular now importing natural gas in ever greater quantities and international prices continuing to climb, Tullow believes the acquisition has huge potential and plans to link the field to the European grid via the Netherlands.

It is understood that Chevron Texaco had not developed the site because it did not offer the economies of scale demanded by a multinational of its size.

Mr Aidan Heavey, Tullow chief executive, said the deal strengthened Tullow's asset base "at a time when the depletion of UK gas reserves is placing upward pressure on prices and increasing the strategic value of gas infrastructure".

However, analysts said that in the wake of the Gabon announcement there was a perception that Tullow wasn't living up to its potential.

"There's a bit of disappointment that their exploration policy isn't really coming up with the goods," said Mr Peter Hitchens, of brokers Cheuvreux UK.