(ADVISORY- Follow European and UK stock markets in real time on the Reuters Live Markets blog on Eikon, see cpurl://apps.cp./cms/?pageId=livemarkets)
* FTSE 100 down 0.6 pct
* Pearson announces Penguin stake sale, shares reverse course
* M&S falls after weak food sales
* Miners lend support
* Carillion extends losses
By Kit Rees
LONDON, July 11 (Reuters) - Britain's top share index retreated on Tuesday as falls in defensive stocks as well as Pearson and Marks & Spencer overshadowed gains in miners.
The blue chip FTSE 100 index was down 0.6 percent at 7,323.21 points by 0854 GMT, while mid caps were 0.5 percent lower.
Defensive firms and dollar earners were among the biggest weights on the index. They included British American Tobacco , AstraZeneca and Diageo, as well as energy firms Royal Dutch Shell and BP.
"There's a bit of strength coming through in the pound, which is causing some of the exporters and bond proxy stocks to have some weakness," Jonathan Roy, advisory investment manager at Charles Hanover Investments, said.
Education publisher Pearson was the biggest faller, down 6.7 percent and giving up early gains after agreeing to sell a 22 percent stake in book publisher Penguin Random House for around $1 billion in a bid to boost its balance sheet and return cash to shareholders.
Investors initially reacted positively to the news but others saw the move as insufficient.
Pearson's shares have fallen nearly 20 percent this year, struggling after a string of profit warnings as the group battles to get to grips with the rise of digital learning.
"Pearson is stripping back from their core businesses, and are they selling the family china?" Charles Hanover Investments' Roy said.
"What this is doing is degenerating their core revenue generation model. So, yes, in the short term you've got some capital, but how are you going to earn money going forward?"
Marks & Spencer was also punished after a trading update, tumbling 3.5 percent, on rising concern about food sales.
Though the retailer said its recovery plan was on track and it stuck to its guidance for its 2017-18 financial year, analysts were disappointed by a 0.1 percent dip in like-for-like M&S food sales in its fiscal first quarter.
"With Clothing & Home in line, the concern now relates to (Marks & Spencer's) Food business, which has underperformed the industry for the second quarter in a row," analysts at Investec said in a note.
Shares in peers Tesco and Morrison rose 0.9 percent and 0.8 percent respectively.
Among risers, mining firms Anglo American, Glencore and Antofagasta enjoyed gains after the underlying price of copper rose.
Among mid-caps, construction company Carillion continued to suffer fallout after its CEO stepped down amidst a full-year profit warning on Monday. It was down another 15.5 percent after plunging nearly 40 percent on Monday.
Reporting by Kit Rees; Editing by Susan Fenton