* FTSE 100 rises 0.6%, FTSE 250 up 0.3%

Sept 14 (Reuters) - UK shares rose on Monday as drugmaker AstraZeneca resumed trials of its COVID-19 vaccine, while Brexit fears simmered ahead of a parliament vote on a plan to break international law by breaching parts of the divorce treaty with the European Union.

The House of Commons will debate the Internal Market Bill, which the EU has demanded Prime Minister Boris Johnson scrap by the end of September. After the debate, lawmakers will decide if it should go to the next stage.

The blue-chip FTSE 100 rose 0.6% in early trading, with a 0.8% gain for AstraZeneca Plc among the top boosts to the index.

The drugmaker said over the weekend it had resumed British clinical trials of its COVID-19 vaccine, one of the most advanced in development, after getting the green light from safety watchdogs.

The mid-cap FTSE 250 added 0.3%, with Oxford BioMedica leading gains. (Reporting by Shashank Nayar in Bengaluru; Editing by Subhranshu Sahu)