The GBP/USD currency pair, which expresses the value of the British pound sterling in terms of the U.S. dollar, has pushed higher since the latter half of July this year. Yet in recent weeks, GBP has struggled to sustain its advance against USD. The chart below uses weekly candlesticks to illustrate GBP/USD price action from around 2017 through to present.
(Source: Trading View.)
The U.S. dollar has sold off against various currencies, including perhaps most notably the euro, as markets have become less convinced of the world reserve currency's entitlement to a premium.