UPDATE 1-Tesco CEO does not see job at risk as market share falls

* Tesco market share falls to 10-year low of 28.7 pct

* CEO doesn't expect to be in top job as long as predecessor

* Clarke declines comment on future of CFO

* Tesco cuts prices, revamps stores

* Shares down 0.4 percent, not far from 16-month low

By Emma Thomasson

LONDON, March 12 (Reuters) - Tesco Plc ChiefExecutive Philip Clarke does not feel investors are running outof patience with his leadership even after the market share ofBritain's biggest retailer fell to a decade low, he said onWednesday.

Tesco, the world's third-largest retailer, is 22 months intoa turnaround programme under Clarke, but sales are still fallingat its 3,150 British stores despite spending on refits, morestaff and new product ranges.

The retailer, whose slogan is "Every Little Helps", is beingsqueezed in its home market between hard discounters Aldi and Lidl on the one hand and moreupmarket brands Waitrose (part of John Lewis ) andMarks & Spencer Plc on the other.

Its market share fell to 28.7 percent - the lowest since2004 - in the 12 weeks to March 2, from 29.6 percent in the sameperiod a year before, data from market researcher KantarWorldpanel showed on Tuesday.

Speaking at the annual Retail Week Live conference, Clarke,who took over as CEO in 2011 after a long career at Tesco, saidhe did not expect to be in the job as long as his predecessorTerry Leahy, who led the company for 13 years.

"You only have a job like this for a few years," he said. "I am not a young man, I'm 54 years of age and I've given it40 years."

Asked if that meant investors were saying his time wasrunning out, Clarke said: "I don't feel it at all. What I feelis a much greater obligation to the company and thestakeholders... customers, colleagues and shareholders.

"It's not a question about discounters or something else,it's about doing the right thing for our customers."

Tesco shares were down 0.4 percent at 314.3 pence by 1134GMT, not far from a 16-month low of 313.2p set last month. Thestock trades on a multiple of 11 times year-ahead forecastearnings, a 23 percent discount to UK peers, according toReuters data.

TIME LAG

Clarke, whose father was a Tesco store manager, joined thecompany as a shelf-stacker in 1974 and was then hired as amanagement trainee after graduating with a degree in economichistory. He joined the board as supply chain director in 1998.

He declined to comment on a Sky News report that ChiefFinance Officer Laurie McIlwee, who has been with Tesco since2009, was likely to leave in the next few months amid tensionswith the CEO.

"Big companies take a long time to change, we have more than3,000 stores ... That takes time," Clarke said. "I know ourbusiness is getting better. There is a lag between it gettingbetter and people talking about it."

Clarke said last month Tesco, which ranks third globally bysales after Walmart Stores Inc and Carrefour SA, would cut prices as he effectively abandoned a targetfor a UK operating margin of 5.2 percent, the highest in theindustry, adding he would also speed up store revamps andinvestment in online and convenience channels.

At Tuesday's conference, Clarke stressed the importance of ashift to smaller stores as consumers around the world move froma big weekly shop to more frequent, smaller purchases. "Peopleliving their lives on the go want to grab and go," he said."Bigger is no longer seen as better by today's customer."

Wal-Mart said last month it was doubling the number ofsmaller new stores it planned to open this year to combatsluggish sales, broaden its customer base and fend off rivals.

Clarke said convenience stores were among Tesco'shighest-returning investments and performance was improvingfurther as the company adjusted its supply chain to the format.

Separately on Wednesday Tesco launched a UK fuel savingpromotion that will involve investment of a magnitude similar tothe 200 million pounds ($332.55 million)of price cuts itannounced last month.

It said Clubcard Fuel Save awards holders of its loyaltycard a 2p fuel discount for every 50 pounds spent in a month,though customers don't have to spend 50 pounds all at once.