LONDON, Oct 4 (Reuters) - Sterling eased against the euro and the dollar on Thursday, with investors citing position adjustment on the slim chance the Bank of England may administer a surprise rate cut later in the session.

All economists polled by Reuters see rates on hold at 5.75 percent, with the median chance of a cut at 15 percent. Markets however are pricing in a likelihood of 20 percent or more.

"If you look at the analyst polls, it's clear that the bank should do nothing but it's far less clear cut than that ... Some people are a little bit fearful that the central bank could spring a surprise on us," said Jeremy Stretch, currency strategist at Rabobank.

"It probably makes sense to remain short sterling until 12.01 pm," he added.

The BoE decision is due at 12 noon (1100 GMT).

By 0702 GMT, the euro gained 0.23 percent at 69.46 pence <EURGBP=>, but still below last month's 2-1/2 year peaks of 70.29 pence.

The European Central Bank is also expected to leave rates on hold on Thursday, but unlike the BoE it is seen retaining a hawkish bias.

On a trade-weighted basis, sterling opened 0.1 percent lower at 102.5 <=GBP>. Against the dollar, it was a touch softer at $2.0294 <GBP=>.

The BoE does not usually issue a statement when it leaves rates unchanged, although it broke with that tradition last month to comment on the credit market squeeze and the troubles that caused at UK mortgage lender Northern Rock. Data on Thursday gave further proof of a slowdown in Britain's housing market, with the September Halifax house price index falling 0.6 percent on the month.