Prideaux joins the insurer in the new role of group communications director, with responsibility for Aviva's corporate media relations and internal communications worldwide.
He was most recently a partner at City PR agency Brunswick, where he worked on Aviva's takeover of RAC in 2005. He joined Brunswick from a corporate finance role at bank ING Barings in 1995.
Stimpson, currently group external affairs director, will take up the new role of corporate affairs director for Aviva's UK business, with responsibility for media relations, public affairs and internal communications.
Amanda Mackenzie, chief marketing officer, said: ‘Hayley and Nigel both have first class track records of delivery in financial services communications. I am delighted that Nigel is joining Aviva and these appointments demonstrate the investment we're making in building our communications and marketing capability as we develop Aviva as a global brand.'
The firm said that the creation of a single communications function reflects its intention to raise the profile of the Aviva brand in the UK after it brought together its UK businesses in 2009.
Prideaux commented: ‘Aviva is an excellent global business and a powerful brand with significant potential. I am looking forward to working with the strong team at Aviva to help realise that potential.'