The pound has climbed to its highest level against the dollar in a month after the greenback reacted nervously to US President Trump's protectionist, strident inauguration speech.
Sterling rose by a cent against the dollar to just under $1.25. The pound was also ahead against the euro.
Sterling's strength weighed down UK-listed shares, leaving the FTSE 100 – after its record-breaking start to January – down by about 0.5%, close to its level at the beginning of the year.
Shares in the FTSE's multinational companies tend to benefit from the weaker pound, as this makes their foreign currency earnings worth more in sterling terms.
The dollar was on the back foot as markets digested the protectionist rhetoric of Mr Trump's inauguration speech.
A weekend of protest and confrontation between the White House and the media, together with confirmation that the US intends to withdraw from the Trans-Pacific Partnership trade deal, added to the negative sentiment.
US markets had been broadly cheered by Trump's election, with hopes that an infrastructure spending boost and lower regulation and taxes would lift business.
But Rabobank strategist Philip Marey said, however, that the new President's rhetoric "sparked some concerns in the markets that he is going to play hard ball".
Kathleen Brooks, research director at City Index, said: "The initial reaction to the first few days of Donald Trump's presidency suggests that investors may be losing patience with the new occupant of the White House."
She said investors were worried about "protectionism and what a deeply unpopular president will mean for national unity and international diplomacy over the next four years".
The International Monetary Fund has warned that a "destructive" trade war could derail global growth.
It followed Trump's threats to slap punitive tariffs on carmakers in Mexico exporting to the US, as well as confrontational campaign rhetoric over China.
The pound's climb on Monday follows a sharp surge last week – its strongest one-day rise since 2008 – as Theresa May's Brexit speech was viewed as less "hawkish" than expected on the terms of the EU divorce. It is still 17% down in the wake of the EU referendum in June. The 'Yes' vote sent the currency to its lowest level against the dollar since 1985.
Additional reporting by IRN
