The great “on again, off again” saga on when the next US interest rate rise is going to come has taken another twist. The US jobs figures for July, showing a surprisingly strong monthly increase of 255,000, has meant an increase in September is very much back on the agenda.

The US Federal Reserve Board will have one more set of jobs data before it has to decide on whether to announce the second rate hike since as far back as 2016. It first moved last December, when it put the target level for the Fed Funds rate up from 0 to 0.25 per cent to 0.25 to 0.5 per cent. Another 0.25 per cent hike had been expected in June, but weak data meant Janet Yellen and the rest of the Fed committee members had to hold off. Now, however, the lights are flashing orange and they could turn green if there is no unexpectedly bad data in the weeks ahead.

Currency analysts speculate that this could lead to funds moving in to the US dollar and out of sterling, where interest rates were lowered during the week and could conceivably fall again if the UK economy does not pick up. There is no great science to the Bank of England action, which is akin to throwing paint at a wall and hoping it will stick. If it doesn’t, then there is even speculation that UK base rates could be cut as low as 0.1 per cent.

There are dangers here for Ireland, of course. Lower UK rates have already pushed sterling lower. However with euro zone rates at rock bottom, too, sterling could lose more against the US dollar than against the euro. Lower UK economic growth is also negative for Ireland, though continued recovery in the US would be some consolation.

In a longer-term sense, the extraordinarily low level of central bank interest rates is unprecedented in modern times. We can only hope that the medicine works, because the doctors may not be able to up the dose much more. Mark Carney’s move this week is bold, to say the least. However we will know that once you have thrown in the kitchen sink, you can quickly start running out of options.