Pearson slump, weak energy shares hit Britain's FTSE

* FTSE 100 index down 0.9 percent

* Pearson (Xetra: 858266 - news) shares sink after update

* Energy shares track weaker oil prices (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)

By Atul Prakash

LONDON, Oct (Shenzhen: 000069.SZ - news) 17 (Reuters) - Publisher Pearson led Britain's top share index lower on Monday after saying market conditions continued to be challenging.

The blue-chip FTSE 100 index was down 0.9 percent at 6,947.55 points at the close after climbing to a record high last week. Britain's mid-cap index was down 1 percent.

Pearson was down 8.4 percent after reporting a 7 percent drop in its nine-month organic sales and saying retailers had further corrected their inventory demands in July and August.

"Pearson is now relying on its core educational businesses for forward momentum, but convincing customers to continue paying for its content represents a huge challenge," Hargreaves Lansdown analyst George Salmon said.

"Despite enjoying the benefits of a weaker pound, sales have been falling recently and there was little in today's update to suggest that the tide is changing."

Energy shares also lost ground after oil prices fell, pulled down by a rising rig count in the United States, a strong dollar and record OPEC output, which comes amid slowing global economic growth that could erode demand for fuel.

The UK oil and gas index fell more than 1 percent, dragged down by a 1.2 to 1.7 percent fall in shares of BP, Royal Dutch Shell (Xetra: A0ET6Q - news) and Tullow Oil (LSE: TLW.L - news) .

Among mid-cap companies, Debenhams (Other OTC: DBHSF - news) fell over 2 percent after Morgan Stanley (Xetra: 885836 - news) downgraded its rating on the stock to "equal-weight" from "overweight".

(Reporting by Atul Prakash; editing by John Stonestreet)