LONDON, 21 January 2008 – Aon Limited, the UK’s largest insurance broker and risk adviser, has appointed Robert Brown as CEO of its Corporate division. Aon Corporate includes the company’s Commercial Insurance (targeting mid-large UK businesses), Professional Services Group and Aon Trade Credit operations.

Robert joined Aon in 2001 and was most recently head of risk transfer for Aon Global UK, responsible for programme design and placement for large UK corporate and multinational clients.

Peter Harmer, CEO of Aon Limited, commented: “Robert has a deep knowledge of the marketplace Aon Corporate operates in, gained from 24 years in the industry. He is a highly regarded practitioner, passionate about his clients and with a reputation for working closely with them to protect and grow their wealth.

“It is a very tough marketplace in the mid-large UK corporate sector. Robert’s track record for building and leading high-performing teams and his reputation for integrity and courage make him the ideal choice to lead Aon Corporate.”

Robert replaces John Thornton, who has left Aon to pursue other opportunities.

Peter Harmer commented: “We are very grateful to John for the hard work and commitment he has always displayed as one of our senior leaders. He has developed and established strategic initiatives that will help us grow in 2008 and beyond and we wish him well for the future.”

Ends

For more information contact:

Reuben Aitchison

020 7086 7201

reuben.aitchison@aon.co.uk

About Aon

Aon Corporation (NYSE:AOC) is the leading global provider of risk management services, insurance and reinsurance brokerage, human capital and management consulting, and specialty insurance underwriting. Through its 43,000 professionals worldwide, Aon readily delivers distinctive client value via innovative and effective risk management and workforce productivity solutions. Our industry-leading global resources, technical expertise and industry knowledge are delivered locally through more than 500 offices in more than 120 countries. Aon was ranked by A.M. Best as the number one global insurance brokerage in 2007 based on brokerage revenues, and voted best insurance intermediary, best reinsurance intermediary, and best employee benefits consulting firm in 2007 by the readers of Business Insurance. For more information on Aon, log onto www.aon.com.

This press release contains certain statements related to future results, or states our intentions, beliefs and expectations or predictions for the future which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from either historical or anticipated results depending on a variety of factors. Potential factors that could impact results include: general economic conditions in different countries in which we do business around the world, changes in global equity and fixed income markets that could affect the return on invested assets, fluctuations in exchange and interest rates that could influence revenue and expense, rating agency actions that could affect our ability to borrow funds, funding of our various pension plans, changes in the competitive environment, our ability to implement restructuring initiatives and other initiatives intended to yield cost savings, our ability to successfully execute strategic options for our Combined Insurance subsidiary, the impact of current, pending and future regulatory and legislative actions that affect our ability to market and sell, and be reimbursed at current levels for, our Sterling subsidiary’s Medicare Advantage health plans, changes in commercial property and casualty markets and commercial premium rates that could impact revenues, changes in revenues and earnings due to the elimination of contingent commissions, other uncertainties surrounding a new compensation model, the impact of investigations brought by state attorneys general, state insurance regulators, federal prosecutors, and federal regulators, the impact of class actions and individual lawsuits including client class actions, securities class actions, derivative actions, ERISA class actions, the impact of the analysis of practices relating to stock options, the cost of resolution of other contingent liabilities and loss contingencies, and the difference in ultimate paid claims in our underwriting companies from actuarial estimates.  Further information concerning the Company and its business, including factors that potentially could materially affect the Company’s financial results, is contained in the Company’s filings with the Securities and Exchange Commission.

Aon Limited is authorised and regulated by the Financial Services Authority in respect of insurance mediation activities only.