Bean's comments to a regional newspaper came at the same time as long-standing hawk Andrew Sentance reiterated his call for higher rates and warned that the BoE risked losing its inflation-fighting credibility if it did not act soon.Both policymakers indicated they were not overly concerned by the 0.5 percent economic contraction at the end of last year, suggesting that may not deter them from tightening policy.Surveys this week showing manufacturing growth picked up and construction rebounded from a weather-related fall in December, imply the economy made a solid start to 2011.Interest rate futures fell sharply in the wake of the latest figures and the pound climbed, as investors bet the BoE would raise rates sooner rather than later.Bean said the bank still expected inflation to fall back toward its 2 percent target, providing there were no further price shocks, but if commodity prices remained high in the medium term, policymakers would have to act."We may well have to respond to that by keeping domestically-generated inflation lower," Bean was quoted as saying in the Western Mail newspaper.He said a rate rise could be made in the context of strong growth."On the other hand if it is in response to a spike in oil prices that we think is likely to persist and inflation is becoming embedded that is not a nice reason to raise interest rates, but we would have to do it."That certainly could be one driver of a change in interest rates if we thought it materially affected the medium-term outlook."Bean's comments highlight the growing concern among policymakers that the external factors driving up prices, which they have so far shrugged off as being temporary, could become a permanent fixture and start to fuel a wage-price spiral.A second member of the nine-man Monetary Policy Committee, Martin Weale, joined Sentance in voting for a quarter-point hike in January, and for other members the decision was a "finely balanced" one, minutes of that meeting showed.Nonetheless, analysts said policymakers were unlikely to make the leap to higher rates at their meeting next week, although there is a strong possibility of a move by May."I think February is probably off the cards: They're going to want to see clear evidence of an improvement in GDP," said George Buckley, economist at Deutsche Bank."These are very uncertain times: The MPC will want to be sure that when they do start tightening policy, it is the right time to do it and it won't threaten the recovery."With inflation at almost double its 2 percent target and likely to rise even further, the BoE must act soon to safeguard its inflation-fighting credibility, Sentance said."The longer we delay (monetary tightening) the more there is a risk that interest rate rises when they come will have to be larger, and then there will be a bigger risk of a shock to confidence," Sentance told the CityAM newspaper."We need to be prepared to look through fluctuations in GDP growth when we're recovering from recession: Growth figures are never linear and smooth in recoveries."Policymakers will have their updated inflation and growth forecasts when they make their decision next week, and these are likely to show inflation picking up sharply in the coming months to almost 5 percent — 3 percentage points above target.Analysts say a strong reading on tomorrow's services PMI survey could embolden those policymakers who were wavering to vote for an increase before the next forecasting round in May."Even if they don't go in February, I am not sure we're going to have until May. The Inflation Report could tee us up for a March or April hike," said Ross Walker at RBS."If we get an outsize bounce in the services PMI on Thursday, it's toss a coin time — it's really going to be close."The government's program of tax hikes and spending cuts add a further complication to the BoE's decision-making process.But any let-up in the pace of cuts may give the BoE the green light to raise rates, the Institute for Fiscal Studies said on Wednesday."Any fiscal loosening aimed at helping the economy could be ineffective if it prompts an offsetting monetary tightening," the think-tank said.