Aon has been dealt a blow to its classic car business with the loss of a senior director to a rival.

Denise Pitwell, a high profile director of Aon Automotive - now part of Aon Private Clients - is to join broker Aston Scott next month.

Market sources described Pitwell as a "big player" in the classic car sector and suggested she would be looking to set up a classic car scheme to rival Aon's.

Aston Scott's chief executive, Andrew Scott said Pitwell would focus on building the broker's classic motor trade book of business. "This is an area where we already have expertise, but it is expanding."

Scott added: "Denise will be a very welcome member [of the company] and will be based in our Guildford office." She is to start on 1 July.

Aston Scott specialises in the top end of the classic car market such highly valuable vintage cars and collections. The business also focuses on general commercial insurance and risk management. It has offices in Guildford, Kent and Cornwall.

Aon Automotive merged with Aon Private Clients in November 2004 to bring together Aon's offering for high net worth clients across different insurance lines, such as classic car and high net worth household. It is thought to have around 50,000 customers.

Aon declined to comment on Pitwell's departure.