Mining group Anglo American said increased platinum prices and buoyant diamond sales had helped lift profits to record levels.

The company, part of a consortium bidding to take diamond giant De Beers private, saw profits before tax in the year to December 31 rise to £2.67 billion from £1.95 billion a year earlier.

Its net profit figure rose 54 per cent to a record £1.38 billion.

London-listed Anglo said its platinum operation contributed more than 25 per cent of its net profits, with higher prices offsetting rising mining costs.

Increased diamond sales, driven by the "millennium factor", led to a record contribution from De Beers, in which Anglo has a complex cross-ownership.

A series of acquisitions, together with strong pulp and paper markets, also helped Anglo's forest products division to record a 55 per cent rise in its net profits figure.

The contribution from AngloGold fell following a disappointing operating performance by certain South African mines.

Tony Trahar, chief executive, said Anglo had made "major progress" during the year, although the company warned it was concerned about the slowdown in the US and the resulting effect on commodity prices.

Anglo added: "The group's major operating divisions are all well positioned on the cost curve to generate profits and cash flows during any slowdown.

"In addition the group's balance sheet is conservatively geared."

Last month, Anglo announced it was part of a consortium which made a £12 billion bid for De Beers.

The move, which also involves South Africa's Oppenheimer family, aims to unlock the complex cross-shareholding structure between Anglo and De Beers. At present, Anglo owns 32.2 per cent of De Beers, which in turn owns 35.4 per cent of Anglo.