By Carla Mozee, MarketWatch

LONDON (MarketWatch) -- U.K. equities lost ground Tuesday, with weakness in Diageo PLC shares as the drinks maker sought control of an Indian liquor company, and declines for G4S PLC in the wake of a ratings downgrade.

The FTSE 100 fell 0.3% to 6,561.55, wiping out Monday's rise of the same amount.

Contributing to the FTSE's pullback, shares of Diageo slipped 0.5% as the British company and a Dutch unit offered $1.9 billion to buy another 26% stake in United Spirits Ltd. . The Indian company's brands include McDowell's No. 1, Black Dog Scotch whisky and Pinky vodka. A successful bid would push Diageo's stake in United Spirits to nearly 55%.

At the same time, shares of G4S lagged behind all others on the FTSE, falling 4% after Deutsche Bank said it doesn't see significant "hidden value" in G4S to warrant the security company's current valuation, and downgraded its rating on G4S to sell from hold. "We expect a lower Group growth profile in this cycle despite benefits from [emerging markets] exposure. We see limited scope for large cost saving surprises," wrote Deutsche Bank analysts. "We trust the new management's plans for the business can improve operating results however in our view the benefits are more than priced in."

But Aggreko PLC was among the index's top percentage gainers, with a 2% rise after the temporary-power provider said it's made "an encouraging start to the year," with two of three regions delivering strong revenue growth in the first quarter. Its local business is showing underlying revenue up 11% in the first quarter.

Engineering company GKN PLC said demand in its principal markets in line with its expectations. The shares traded 1.3% higher.

On the economic front, U.K. inflation slowed in March to its lowest annual rate since October 2009. Annual inflation was 1.6% in March, down from 1.7% in February, said the Office for National Statistics. The Bank of England's inflation target is 2%.

"Considering the movements in producer prices, we believe that inflation is unlikely to move up in the coming months," said ICICI Bank in a note Tuesday, adding that it expects the Bank of England to hold monetary policy unchanged this year.

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