Warren Buffett’s Berkshire Hathaway was hit by a $1.6bn first-quarter non-cash loss on derivatives contracts – an asset class he once described as “financial weapons of mass destruction.

The surprise investment loss, announced on the eve of Berkshire’s annual meeting in Mr Buffett’s native Omaha, caused a 64 per cent plunge in first quarter profits to $940m, from $2.6bn in the same period last year.