Britain's FTSE underperforms after falls for as Ashtead and Burberry

* FTSE 100 down flat

* Ashtead, Intu Properties (Other OTC: CCRGF - news) slip on downgrade

* Burberry lower as European luxury sector falls

* Costa boss departure hits Whitbread (ADVISORY- Reuters plans to replace intra-day European and UK stock market reports with a Live Markets blog on Eikon - see cpurl://apps.cp./cms/?pageId=livemarkets for site in development. See the bottom of the report for more details)

By Alistair Smout and Kit Rees

LONDON, April 12 (Reuters) - UK shares stumbled on Tuesday in choppy trade, after a broker downgrades hit the shares of Ashtead Group (LSE: AHT.L - news) , while a fall in the European luxury sector weighed on Burberry.

The blue-chip FTSE 100 index was flat at 6,200.67 points by 1151 GMT, slightly underperforming the broader European market.

The top faller on the index was equipment rental company Ashtead Group, which dropped nearly 4 percent after investment bank HSBC downgraded its rating on the stock to "hold" from "buy" based on findings about the age of its fleet.

"Upon a closer examination, Ashtead's fleet may not be materially younger than that of the peers, at least on a basis that matters commercially," analysts at HSBC said in a note.

Intu Properties also suffered from a target price cut from Societe Generale (Swiss: 519928.SW - news) , which sent its shares 2.3 percent lower.

Hospitality company Whitbread (LSE: WTB.L - news) fell 1.9 percent after the boss of Costa, a chain of coffee shops which it operates, left the company.

"Whilst the company has certainly lost a lot of internally generated knowledge/talent, we believe the board has sought to bring news skills to the group especially as it embarks on an ambitious and more internationally focused phase of growth," analysts at Credit Suisse (LSE: 0QP5.L - news) said in a note.

Luxury goods company Burberry was also lower, down 2.4 percent following a miss in Q1 earnings from its French peer LVMH, which was impacted by subdued tourist shopping in key markets such as France and Hong Kong.

Miners were the top gainers, led higher by a 7.1 percent rise in Anglo American (LSE: AAL.L - news) . The company said that rough diamond sales during the third cycle of the year continued their reasonably positive trend.

The mining sector was up 3.6 percent, supported by steady copper prices and encouraging economic signals from China.

"Commodities have been rallying very strongly since about February ... and that has obviously given miners a bit of a tailwind," Ken Odeluga, market analyst at City Index, said.

ADVISORY- Reuters plans to replace intra-day European and UK stock market reports with a Live Markets blog on Eikon (see cpurl://apps.cp./cms/?pageId=livemarkets for site in development). In a real-time, multimedia format from 0600 London time through the 1630 closing bell, it will include the best of our market reporting, Stocks Buzz service, Eikon graphics, Reuters pictures, eye-catching research and market zeitgeist. Breaking news and dramatic market moves will continue to be alerted to all clients and we will continue to provide a short opening story and comprehensive closing reports.

If you have any thoughts, suggestions or feedback on this, please email mike.dolan@thomsonreuters.com.

Mike Dolan, Markets Editor EMEA. (Reporting by Kit Rees)