The BBC has begun the search for a new non-executive chairman of BBC Worldwide, the arm responsible for sales of programmes overseas and merchandising. Robert Webb QC, the previous incumbent, stepped down last week. The BBC\'s executive board, led by director general Mark Thompson and senior independent director Marcus Agius, the Barclays chairman, will make the appointment. BBC Worldwide made pre-tax profits of £201m on sales of £1.16bn in the year to March 2011.