London's top flight index slumped into the red as sterling touched a six-month high against the US dollar after investors were left underwhelmed by President Donald Trump's tax plans.
The FTSE 100 Index closed down 51.55 points at 7,237.17, while the pound enjoyed an uplift on the greenback's weakness in response to a lack of detail outside Mr Trump's broad pledge to slash corporation tax to 15% from 35%.
The UK currency was also making gains against the euro after the European Central Bank (ECB) kept its stimulus programme and interest rates unchanged, despite conceding that the eurozone economy is becoming stronger.
Sterling was up 0.4% against the US dollar at 1.289 and was 0.7% higher versus the euro at 1.185.
Across Europe, Germany's Dax was down 0.2% and the Cac 40 in France slipped by 0.3%.
On the oil markets, Brent crude dropped 2.2% to 50.68 US dollars a barrel after two oilfields in Libya resumed production, exacerbating concerns over the global supply glut.
In a busy day for UK stocks, housebuilder Persimmon raced ahead after a healthy trading update that revealed an 11% surge in forward home sales since the start of the year.
Shares rose more than 2%, or 54p to 2,340p, after the Charles Church group said total forward sales, including legal completions, had leapt to £2.6 billion in the year so far, up from £2.3 billion a year earlier.
Rival Taylor Wimpey also enjoyed a shares boost despite setting aside £130 million as part of plans to help customers trapped in onerous leasehold contracts drawn up by the housebuilder.
Following a review of lease agreements struck over the past decade, the company also issued an apology for the "unintended financial consequence and concern" for what MPs dubbed the "PPI of the housebuilding industry".
The firm ended the day up 3.1p at 201.6p.
Lloyds Banking Group emerged as a top performer, with investors cheering a robust update that saw the high street lender double its profit in the first three months of the year.
The bank closed up 1.6p at 68.97p after posting a better-than-expected set of first-quarter figures, with pre-tax profits surging to £1.3 billion, up from £654 million a year earlier.
This came despite the bank being forced to set aside £350 million to cover mis-sold payment protection insurance (PPI) claims and £100 million to cover compensation for victims of fraud by former HBOS staff.
In a contrast of fortunes, advertising giant WPP was rooted in the red after its first-quarter update, which saw the Brexit-hit pound and strong UK growth boost revenues despite US sales falling.
The group booked a 17% jump in reported revenues to £3.6 billion for the first quarter, with net sales climbing 19% as the firm enjoyed an added boost after translating overseas earnings back into pounds.
Shares were down 42p to 1,680p.
The biggest risers on the FTSE 100 Index were Mediclinic International up 128p to 859p, Kingfisher up 9p to 335.8p, Persimmon up 54p to 2,340p, Lloyds Banking Group up 1.6p to 68.97p.
The biggest fallers on the FTSE 100 Index were Legal and General down 14.2p to 246.9p, BHP Billiton down 57.5p to 1,153.5p, ITV down 8.9p to 210.5p, Fresnillo down 57p to 1,436p.