Christophe de Margerie, chief executive of French oil and gas giant Total, told Scottish industry leaders that the era of cheap oil was over but said the UK government needed to help the industry on the tax front.

Speaking at Friday's Scottish Oil Club dinner, de Margerie said that the days of $30-a-barrel oil, upon which firms used to plan capital projects, had ended as a result of a phenomenal increase in demand for energy.

The Frenchman, who was promoted to the top job at Total last month, told the Edinburgh gathering that $50 oil was probably also a thing of the past.

However, in an apparent warning to the Chancellor of the Exchequer not to take advantage of strong oil prices to increase taxes in this month's Budget, he told the gathering in Edinburgh: "But please don't tell Gordon Brown."

Noting that while gas prices had fallen sharply in recent months the costs of operating had continued to increase, de Margerie said that the government could have a crucial role in ensuring that marginal projects went ahead.

For example, he said, without tax breaks Total might not be able to proceed with major developments west of Shetlands.

These would involve operating in areas of high temperature and high pressure away from infrastructure.

However, de Margerie also put the onus on oil and gas companies to make life easier for themselves by changing the way they acted.

He said that international oil companies needed to show more sensitivity to the countries in which they operated, in comments which suggest that a recent and bruising encounter with the Venezuelan authorities has made an impression on Total directors.

After surrendering a small field to the socialist government last year, Total is under pressure to cede control of a huge heavy oil project in the Orinoco region to PDVSA, the state-owned oil company.

The 55-year-old de Margerie, who belongs to the Taittinger champagne family, also said exploration and production firms had to work more closely with services players.