Update: The FTSE 100 has closed down, despite the pressure from a stronger pound easing as a dollar sell-off sparked by US president Donald Trump calmed.
The UK blue-chip index closed 21 points, or 0.3%, at 7,328, despite the pound ending the day down against the dollar, which recovered from a slump sparked by Trump's comments the greenback was 'too strong'.
But it's still been a strong week for the pound, currently changing hands at $1.252, up from $1.237 earlier in the week. A stronger pound tends to hamper the FTSE 100, whose members rely on overseas markets for around three-quarters of their revenues.
Trump said in an interview with the Wall Street Journal the dollar was 'getting too strong' and that he would prefer the US Federal Reserve keep interest rates low.
'I think our dollar is getting too strong, and partially that's my fault because people have confidence in me,' he said. 'But that's hurting - that will hurt ultimately. It's very, very hard to compete when you have a strong dollar and other countries are devaluing their currency.'
But in a marked shift, Trump refused to label China a currency manipulator, having made that claim on the campaign trail, saying it could jeopardise talks with the country over tackling North Korea.
Analysts at Rabobank said the market's response to Trump's election, rallying on prospects of higher growth and inflation, had left the president in a difficult position.
'The Fed's March rate hike and discussion as regards further normalisation of policy (including the unwinding of the Fed's balance sheet) will serve to underpin the view that the economy is indeed on the mend, placing additional pressure on dollar strength,' they said.
'The difficulty for Trump on this front is that this all clearly runs counter to a weaker currency and offers him little room for accusing trade partners (particularly those in regions that are maintaining soft monetary policies of their own) that they are actively manipulating their currencies with a view to damaging the US economy for their own financial gain.'