The pound sterling against the US dollar reached multi-month highs, rising above $ 1.29.
The main driver for the growth of the GBP / USD pair was the weakening of the greenback on a wide front.
Dollar sales fell slightly ahead of the two-day Fed meeting.
Many analysts believe that the results of the July meeting of the US Central Bank are unlikely to support the USD, as the regulator is likely to maintain a soft monetary policy and worsen economic forecasts.
At the same time, experts warn that the pound's positions look vulnerable in the face of uncertainty around Brexit.
Last week, Britain and the European Union exchanged views on the chances of a free trade agreement. Brussels considers this unlikely, but London hopes that such an agreement will be reached in September.
"Given the increased likelihood that there will be no deal, there shouldn't be much optimism about the GBP," strategists at ING said.
Meanwhile, Standard Chartered experts draw attention to the fact that, despite all the harsh statements of the British authorities about the country's withdrawal from the European Union without a deal, negotiations between London and Brussels are still continuing.
"On a number of controversial issues, the positions of the parties even began to converge. At the same time, EU officials note that the British have taken a more realistic and balanced position," they said.
According to analysts, the main obstacle to an agreement is now the issue of government subsidies and fishing rules.
"While the British government views fishing as a key political issue, it (fishing) provides very little added value to the country's economy, and the main export of fish from Britain is to the European market. Therefore, it is very likely that this issue will turn out to be a bargaining chip when it comes to other aspects of the negotiations, "- said representatives of Standard Chartered.
The bank does not expect a quick breakthrough in the negotiations and believes that they may drag on until October-November.
"Uncertainty around Britain's exit from the EU will remain a negative factor for the pound for the foreseeable future. However, the latest news suggests an increase in the chances of a favorable end to the Brexit saga, and in this scenario, the probability of which is estimated at 50%, we expect to see a rally in GBP / USD by the end of the year, "Standard Chartered said.
The bank's strategists estimate the likelihood of a negative scenario in which the United Kingdom will leave the EU without a deal at 30%. In addition, in their opinion, there is a possibility that the negotiators will not have enough time, and London will be forced to ask Brussels to extend the transition period.
