(Reuters) - London's main stock index retreated from its five-and-a-half month high as exporter stocks took a hit from a stronger pound, after the European Union granted Theresa May a short extension to get lawmakers behind her proposed Brexit agreement.
The FTSE 100, whose constituents derive much of their revenue in U.S. dollars, dipped 0.2 percent by 0814 GMT. The more domestically exposed FTSE 250 added 0.2 percent.
Weighing on the main index were drug maker AstraZeneca, which hit a high in the last session on the pound's weakness; GlaxoSmithKline and Unilever.
Oil majors Shell and BP also dragged on the FTSE 100 as crude prices slipped.
Outshining the index was engineering company Smiths Group, which advanced 3.4 percent after it announced plans to separate its struggling healthcare unit and list it in the UK. The gains placed Smiths on course for its best day in more than four months.
The Brexit update also lifted housebuilders, which would suffer in an economy damaged in a disorderly departure from the EU. Barratt and Berkeley rose over 1 percent.
Among midcaps, Aggreko, the world's largest temporary power provider, jumped 6 percent as brokerage Stifel upgraded the stock and said it saw bigger impact than expected from strategic changes by new management.
(Reporting by Muvija M and Yadarisa Shabong in Bengaluru)
