Europe’s largest hedge fund manager cut its leverage by 80% last year even as it was making a double-digit return for investors, according to details published this morning, as an emphasis on risk management helped steer the group through the most difficult period in its industry's history.

Nagi Kawkabani, joint chief executive of UK firm Brevan Howard Asset Management - which with $24.2bn (€17.2bn) has overtaken GLG Partners and Man AHL as Europe's largest hedge fund manager - said the flagship Brevan Howard fund made more than 20% last year, net of fees.