(For a Reuters live blog on U.S., UK and European stock markets, click or type LIVE/ in a news window)

* FTSE 100 up 0.1%, FTSE 250 off 0.1%

May 9 (Reuters) - London stocks wavered on Thursday as investors turned cautious ahead of the Bank of England's interest rate decision later in the day, while energy shares gave a boost to the benchmark index.

As of 7:17 GMT, the blue-chip FTSE 100 edged up 0.1% at 8,357.85, hovering below its record high of 8,365.28 points. The mid-cap FTSE 250 edged lower by 0.1%.

The pound slipped against the U.S. dollar and the UK's benchmark 10-year gilt yield was at 4.155% ahead of the decision.

Investors avoided big bets ahead of the BoE's interest rate decision due at 1100 GMT, where the central bank is widely expected to keep borrowing costs steady.

The focus will be on whether policymakers deliver any groundwork for loosening policy. Markets are currently pricing in a 50-50 chance of a June rate cut, and have priced in a cut in August.

IMI Plc jumped 1.1% after the specialised engineering firm confirmed its full-year guidance.

BAE Systems logged marginal gains, rising 0.1% after the defence firm said it was on track to meet guidance for higher earnings and forecast a "further positive momentum".

3i Group fell 3.4% after posting full-year results. (Reporting by Pranav Kashyap in Bengaluru; Editing by Mrigank Dhaniwala)