(For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window) * FTSE 100 up 0.3%, FTSE 250 down 0.1% Dec 7 (Reuters) - The exporter-heavy FTSE 100 edged up on Monday, as the pound dipped on fears that Britain’s transition period out of the European Union would expire without the two sides agreeing on a free trade deal. The blue-chip FTSE 100 was up 0.3% by 0802 GMT and was set for a sixth straight session of gains as Britain also prepared to roll out Pfizer-BioNTech COVID-19 vaccine this week. The mid-cap FTSE 250, considered a barometer of Brexit sentiment, dipped 0.1%, led by the industrials and consumer discretionary sectors. Britain and the European Union will make a last-ditch attempt to strike a post-Brexit trade deal this week, striving to solve key sticking points in fishing, governance rules and dispute resolution. Fashion retailer Ted Baker slipped 1.5% as its half-year losses ballooned due to coronavirus-led lockdowns denting retail sales. (Reporting by Shivani Kumaresan in Bengaluru; Editing by Arun Koyyur)