3i, the UK buyout group, this morning gave its clearest signal that most of its portfolio companies are improving in value, two years after Michael Queen took over as chief executive and began a restructuring to relieve the debt-laden company of old, underperforming assets and volatile earnings.

Despite 3i announcing this morning that it had taken a £198m writedown of UK portfolio company Enterprise to nil, several of its top portfolio companies' valuations have risen to above their original cost and the majority of its holdings are improving in value.