BANK of England chief economist Spencer Dale has cautioned that a drop in unemployment below 7% would not automatically lead to a change in policy as Threadneedle Street again sought to convince sceptical markets that interest rate rises were years away.

The number of people in Britain claiming jobless benefits had its biggest fall in more than 16 years last month, according to figures published yesterday.

The unemployment rate was 7.7% in the June to August period, unchanged from May to July and in line with most forecasts.

In an effort to boost the economy the Bank, under its new governor Mark Carney, said in August that it would not consider raising interest rates before unemployment fell to 7%. It predicts this will not happen before the third quarter of 2016.

In a speech published yesterday Mr Dale, who is also the Bank's executive director for monetary policy, warned that it was not the job of the bank to target employment levels.

"Monetary policy can't control the level of unemployment in the long run: we can't generate sustainably higher output or employment simply by printing more money. That way lies the horrors of the high and variable inflation rates of the 1970s and 80s," he said.

Rather the Bank's rate-setting Monetary Policy Committee will use a fall in the jobless rate below 7% as an opportunity to reassess the state of the economy.

"An unemployment rate of 7% is not our intended destination. Nor even is it necessarily the first turning on the way to our final destination," Mr Dale said

"Rather, it is a conveniently located lay-by at which we can pull over, study our economic map in detail, and work out whether we are anywhere close to our first turning."

The forward guidance issued by the Bank, which includes the employment target, supports the trade-off the Bank is seeking to make between bringing inflation down to 2% as quickly as possible without derailing the nascent economic recovery.

He added that the UK economy had picked up and was growing at a rate of 3% to 4% a year,.

But he said the overall level of economic output remained around 3% below its pre-crisis peak, and the Bank was not close to raising interest rates.

"I don't know how quickly bank rate will begin to rise. That will depend critically on the extent to which productivity recovers as demand increases," he said.

He added: "The inflation target remains front and centre in the conduct of UK monetary policy.

"Price stability remains the primary objective of monetary policy."