Why is FTSE trading lower today?

[Mark Michaels]

[Sam Rondon]

The Financial Times Stock Exchange 100 Index, better known as FTSE 100 Index, is trading at 7,526 this morning, which is a decrease of 0.4%, amid continuous concerns over Brexit.
The worst underperformers today are mining heavyweights, in addition to luxury carmaker Aston Martin (LON:AML), which saw its shares tumble 22% after the company lowered several of its forecast due to underperforming UK and European markets.
“The worry is that the UK could rush out of the European Union without a deal if Johnson fails to negotiate a Brexit deal that could satisfy both parties, a challenge that his predecessor Theresa May couldn’t overcome in more than three years,” said Ipek Ozkardeskaya, senior analyst at London Capital Group.
The British Pound is meanwhile trading at $1.2445 after recording three consecutive daily losses.
“When the ministers return from their holiday in September, the clock will be ticking loudly until the October 31 deadline. This means more downside pressure on the pound.”
The FTSE was previously on a three-day winning streak.