UPDATE 1-Tesco starts $686 mln share buyback

(Adds detail)

LONDON, Oct 18 (Reuters) - Tesco, Britain's biggest
retailer, has started a programme to buy back shares with a
value of up to 500 million pounds ($686 million), it said on
Monday.

The group had said when it published half year results on
Oct. 6 that it could afford to start a multi-year share buyback.

At the time Tesco CEO Ken Murphy denied the buyback was a
tactic to ward off private equity bidders.

Rivals Asda and Morrisons have both succumbed to
private equity bids this year.

Tesco said Citigroup will repurchase shares on its behalf.

($1 = 0.7289 pounds)
(Reporting by James Davey; editing by Sarah Young and Louise
Heavens)