Top flight stocks retreated from record highs as the pound was buoyed by MPs beginning to debate Brexit terms.
The FTSE 100 Index slipped 13.3 points to 7,057.6, as Prime Minister Theresa May and Labour leader Jeremy Corbyn clashed over the government's Brexit strategy, providing hints of what the UK leaving the EU might look like. The FTSE 250 Index fell 19.4 points to 18,053.8.
The pound has been battered in recent days because long-term investors are unsure what trading arrangements the UK will adopt in the future. But blue chip shares have surged as many listed multinationals benefit from earnings in stronger foreign currencies.
Main market stocks have hit all-time intraday highs twice over the past two weeks.
But Spreadex financial analyst Connor Campbell said today (12 October): "Still dining out on the news that the PM has promised MPs a debate on the terms of the Brexit, sterling has surged nearly 1% against the dollar and 1.3% against the euro."
Lloyds Banking Group, eased 0.8p to 52.8p, as it announced plans to axe another 1,230 UK jobs as it carries out a restructuring programme aimed at cutting costs and improving returns.
The job losses will fall across the bank's group operations, retail, customer products and marketing, finance and risk divisions, and are part of a streamlining package first announced in October 2014.
In afternoon trading the biggest risers in the FTSE 100 Index were Glencore (+6.4p to 228.3p), Capita (+11.5p to 595.5p), Hargreaves Lansdown (+17p to 1,277p), Centrica (+2.7p to 215p) and Standard Life (+4.2p to 350.1p).
The biggest fallers in the FTSE 100 Index were Whitbread (-83p to 3,804p), Smiths Group (-22p to 1488p), Smith & Nephew (-18p to 1,226p), Lloyds Banking Group (-0.8p to 52.8p) and Old Mutual (-2.7p to 195p).
In afternoon trading the biggest risers in the FTSE 250 Index were Pagegroup (+18.4p to 386.3p), Bodycote (+19.5p to 640p), Morgan Advanced Materials (+9p to 303p), Hunting (+16.5p to 563.5p) and Electrocomponents (+10.8p to 374.8p).
The biggest fallers in the FTSE 250 Index were Domino's Pizza Group (-18.7p to 354p), Sports Direct International (-14p to 279.6p), Countrywide (-6.4p to 201.2p), Mitchells & Butlers (-6p to 270p) and N Brown (-4.4p to 200.6p).