Britain's FTSE edges up on speculation about dovish Fed

* FTSE 100 up 0.3 pct on speculation about dovish Fed

* Reports of Chinese cash injection boosts miners

* Smiths Group (Other OTC: SMGKF - news) top faller after profit drop

By Francesco Canepa

LONDON, Sept 17 (Reuters) - Britain's top share index edged up on Wednesday, underpinned by speculation that the U.S. Federal Reserve would maintain a pledge on low rates at the end of its policy meeting later in the day.

Traders cited a report in the Wall Street Journal as indicating the Fed could be less hawkish than markets have been expecting, shifting the odds on a change in language as investors try to divine when the central bank will hike interest rates.

At 0741 GMT, the FTSE 100 was up 18.10 points, or 0.3 percent, at 6,810.34 points, erasing losses suffered in the previous session but still stuck within a falling channel started in early September.

Companies which trade basic materials added 4 points FTSE 100, boosted by media reports that China's central bank injected a combined 500 billion yuan ($81 billion) of liquidity into the country's top banks to shore up a faltering economy in the world's top consumers of metals.

"The FTSE 100 remains in its September falling channel...and a breakout might be difficult ahead of such a prominent risk event unless speculation (about a dovish Fed) intensifies markedly," Mike van Dulken, head of research at Accendo Markets, said.

"The China announcement is of course a positive, suggesting a leaning towards easing at a time when growth is under pressure, however...miners and oil may be victim of a busy week and may only make their move once the Fed has shown its latest cards."

Traders were reluctant to place big bets ahead of the Fed's announcement, due after the European market close, and Scotland's independence referendum on Thursday.

Scottish supporters of staying in the United Kingdom are 4 percentage points ahead of secessionists with just a day to go before Scots vote in an independence referendum, three different opinion polls showed.

Uncertainty around the referendum's outcome have hit the pound in recent weeks, providing a silver lining for British exporters, which had been hit by the currency's sharp appreciation in the past year as investors bet on a rate rise by the Bank of England.

British engineering conglomerate Smiths Group cited a strong pound, as well as a weak performance at its medical and detection units, as it reported a 10 percent fall in its full-year headline operating profit, sending the shares down 4.4 percent to the bottom of the FTSE.

Britain's unemployment rate, due to be published at 0830 GMT, is expected to have fallen to 6.3 percent in July, from 6.4 percent in the previous month.

The publication of the Bank of England's minutes, also due at 0830 GMT, was expected to show no change in the voting pattern from the previous meeting, with seven out of nine members of the board voting to keep rates unchanged and two backing a hike. (Reporting By Francesco Canepa; Editing by Toby Chopra)