Eni, the Italian oil and gas company, and its advisers have come under fire for revealing last December what it was prepared to pay for Enterprise Oil, a UK rival.

Vittorio Mincato, Eni's chief executive who was advised by Lazard, surprised the markets when he said his company could not afford to pay more than a small premium to Enterprise Oil's prevailing share price of 620p. Eni made an approach at an undisclosed price, but was rejected.