UK's FTSE buoyed by mining shares, M&S earnings

* FTSE 100 up 0.8 pct

* Glencore (Xetra: A1JAGV - news) on track to reduce debt, mining companies rally

* M&S up on positive profit forecast

* Housebuilders fall on sectoral concerns

By Kit Rees

LONDON Nov 4 (Reuters) - UK shares advanced on Wednesday, buoyed by company results from Marks and Spencer that beat forecasts and hopes that mining commodity Glencore is reducing its debt.

The blue-chip FTSE 100 index was up 0.8 percent at 6,433.08 points at 0922 GMT, broadly in line with other European indexes.

Mining shares topped the index, led by Glencore. Its stock rose 6.4 percent after the company said that it was on track to reduce its debt to $20 billion from $30 billion.

The company also plans to boost liquidity with asset sales and to cut copper output further to help lift prices.

"Given how heavily they've fallen and then subsequently rallied thereafter, we still think they represent good value alongside some other picks in the mining sector," Atif Latif, director of trading at Guardian Stockbrokers, said.

The FT350 mining index led sector gains, rising 3.7 percent. Anglo American (LSE: AAL.L - news) , BHP Billiton (NYSE: BBL - news) , Antofagasta (Other OTC: ANFGF - news) and Rio Tinto (LSE: RIO.L - news) were up 3 to 5.1 percent.

Shares (Berlin: DI6.BE - news) in British retailer Marks and Spencer rose to touch two-and-half month highs, up 3.6 percent. The company raised its annual non-food profit margin forecast and beat first half profit forecasts.

"Not the easiest of halves given the weather, but the increased flexibility in M&S' business model stands out," analysts at Investec (LSE: INVP.L - news) said in a note, reiterating a "buy" rating on the stock.

But British housebuilders fell, with Berkeley, Persimmon (Other OTC: PSMMY - news) , Taylor Wimpey (LSE: TW.L - news) and Barratt Developments (LSE: BDEV.L - news) down 2.2 to 5.3 percent. Traders cited concern over interest rates and valuations in the sector.

In the mid-caps, property services company Countrywide slumped nearly 11.7 percent after it said that its full- year core earnings would be down 2014. Estate agency Foxtons Group was also down, falling 6.5 percent.

Pub operator J D Wetherspoon (LSE: JDW.L - news) was down 4.5 percent after the company reported a fall in first-quarter operating margins. The company blamed higher starting rates for hourly paid staff in October 2014 and August 2015. (Reporting by Kit Rees, editing by Larry King)