This chart from Bloomberg business shows that the rate cut expectations/probability from the Bank of England (BoE) has reached 100 percent, meaning that the market is certain of a rate cut this week. This means that a rate cut alone won't be enough to push the pound lower if one is priced in.
So, if the BoE disappoints, we are going to see big moves in the pound sterling, which as of now is trading at 1.318 against the dollar.