The FTSE 100 <.FTSE> index was seen opening 15-18 points, or up to 0.3 percent, higher on Wednesday, according to financial bookmakers, with sentiment supported by stellar quarterlies from consumer technology bellwether Apple
The Fed's Federal Open Market Committee was expected to release forecasts showing interest rates will be near zero for at least two more years and leave the door open to further bond purchases if Europe's banking problems spill over into the United States.
The FOMC will announce its decision after the European market closes, with no change expected to the U.S. central bank's 0.25 percent interest rate.
While London's blue-chip stock index closed down 30.66 points at 5,751.90 on Tuesday, trading in Asia was upbeat overnight, with the MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> rising 0.7 percent at 6:20 a.m.
On the data front, the Office for National Statistics was due to release fourth-quarter GDP figures at 0930 GMT. The British economy was expected have shrunk 0.1 percent in the final three months of 2011, compared with a 0.6 percent growth rate in the previous quarter.
Also at 0930 GMT, the Bank of England will publish minutes from the January Monetary Policy Committee meeting, which were expected to show the MPC unanimous in deciding to keep rates unchanged.
The Confederation of British Industry will release its industrial trends survey for January at 1100 GMT. The total order book balance was expected to have risen to -20 from -23 in December.
Across the Atlantic, U.S. pending home sales, due at 1500 GMT, were expected to have fallen 1 percent month-on-month in December, after a 7.3 percent drop in November.
(Reporting By Francesco Canepa; Editing by Dan Lalor)