(In paragraph 11, corrects to clarify that Nomura is not M&S'sjoint house broker)
By James Davey
LONDON, March 20 (Reuters) - Marks & Spencer,Britain's biggest clothing retailer, lost market share over thelast three months, industry data showed on Thursday, reversing asmall gain late last year that was heralded by its chiefexecutive as a sign his recovery plan was working.
Data from research group Kantar Worldpanel, seen by Reuters,showed M&S's share of the UK fashion market declined 0.2 percentin the 24 weeks to Feb. 16 and was down 0.4 percent in thelatter 12 weeks of the period.
The figures showed the retailer's share of the keywomenswear market contracted 0.2 percent over the 24 weeks and0.5 percent over the latter 12 weeks.
The loss of share is likely to up the pressure on CEO MarcBolland, who has presided over 10 straight quarters of decliningunderlying sales in M&S's general merchandise division, whichincludes clothing.
Bolland is nearing the end of a three-year, 2.3 billionpound ($3.8 billion) plan to address decades ofunder-investment.
In January he said the womenswear business was showing"early signs of improvement" under the management of a new teamand a re-focus on quality and style.
He highlighted womenswear market share growth of 0.1 percentover the 12 weeks to Nov. 24 - the first growth in three years -and said the firm's spring/summer collection had been wellreceived by the fashion press.
M&S declined to comment on the latest market share data.
Shares in the firm were down 1.2 percent at 467 pence at1254 GMT, valuing the business at 7.64 billion pounds.
The stock is down 7 percent over the last six months, thoughup 18.7 percent over the last year.
FORECAST CUT
Earlier this week brokerage Nomura reduced its 2013-14 and2014-15 pretax profit forecasts on concerns of continued weaktrading at the retailer, which also sells upmarket food.
Its forecast for 2013-14 was cut to 614 million pounds from632 million pounds - a forecast below sector analysts' consensusfigure of 628 million pounds published on M&S's corporatewebsite.
Nomura cut its forecast for 2014-15 to 709 million poundsfrom 724 million pounds.
The brokerage reduced its forecast for M&S's fourth-quarterlike-for-like sales in general merchandise to down 1.5 percentfrom up 1.3 percent previously. It also cut its forecast forfood like-for-like sales in its fourth quarter to flat from up0.3 percent previously.
Easter - which normally boosts trade - falls later thisyear, while M&S's business will not have been helped bywidespread flooding in Britain.
M&S is scheduled to update on fourth quarter, to end-March,trading on April 10 and publish 2013-14 results on May 20.
Separately on Thursday Next, Britain's No. 2clothing retailer, posted a 12 percent rise in 2013-14 pretaxprofit to 695.2 million pounds - a figure that would top M&S'searnings for the first time, based on analysts' forecasts. ($1 = 0.6014 British Pounds) (Editing by David Holmes and Pravin Char)
Marks & Spencer (MKS)