UPDATE 1-Old Mutual sells Buxton UK wealth business for $800 mln

(Adds background, detail, Buxton comment)

LONDON, Dec 19 (Reuters) - Anglo-South African financial services group Old Mutual is selling its UK wealth business run by veteran fund manager Richard Buxton to private equity firm TA Associates for 600 million pounds ($803 million), it said on Tuesday.

The sale of Old Mutual Wealth's single-strategy asset management business - where each fund focuses on one type of asset rather than a mix - is part of a planned break-up of the group.

TA Associates is paying 570 million pounds in cash on or before completion, with 30 million payable afterwards, between 2019 and 2021, Old Mutual said in a statement.

Old Mutual's shares rose 4 percent on the news, to the top of Britain's FTSE-100 index.

The majority of the single-strategy management team, including Buxton, will move with the business, Old Mutual said.

"The management team is delighted to be partnering with TA Associates to buy the single strategy business," Buxton said.

"This is a good outcome for our customers and our staff."

Old Mutual is planning to list the remaining UK multi-asset business of Old Mutual Wealth next year, as it looks to break itself into four parts by the end of 2018.

The company, which started as an insurance company in Cape Town in 1845, has banking, insurance and asset management businesses. It has said it is breaking itself up because regulatory change makes the company too complex to run in its current form.

In addition to a planned demerger and initial public offering of the rest of Old Mutual Wealth, the break-up involves the sale of U.S. firm Old Mutual Asset Management, listing of Old Mutual's emerging markets unit and reduction of its stake in South Africa's Nedbank.

The single-strategy wealth division had assets under management of 25.7 billion pounds at Sept. 30.

($1 = 0.7470 pounds) (Reporting by Carolyn Cohn; Editing by Louise Heavens and Mark Potter)