SHANGHAI, Dec 25 (Reuters) - China stocks rose on Friday to post weekly gains, as the Brexit deal helped lift sentiment and as investors cheered Beijing’s continued policy support. ** The blue-chip CSI300 index rose 0.8%, to 5,042.01, while the Shanghai Composite Index closed 1% higher at 3,396.56. ** The tech-heavy start-up board ChiNext firmed 0.7%, while the STAR50 index inched up 0.1%. ** Leading the gains on Friday, the CSI300 materials index and CSI300 healthcare index jumped 3.2% and 2.5%, respectively. **Britain clinched a narrow Brexit trade deal with the European Union on Thursday, just seven days before it exits one of the world’s biggest trading blocs in its most significant global shift since the loss of empire. ** Also helping soothe worries over the country’s corporate bond defaults, China’s central bank said it will step up its regulation of the bond market in line with the law, vowing “zero tolerance” towards illegal activities. ** For the week, SSEC added 0.1%, while CSI300 index firmed 0.8%, hovering near a five-year high, as Beijing pledged further support for its economy. ** In the annual Central Economic Work Conference, a gathering of top leaders and policymakers to chart the economy’s course in 2021, China said it would maintain support for its economic recovery, avoiding a sudden shift in policy, to help keep growth within a reasonable range in 2021. ** Looking into 2021, the Shanghai index could hit the 4,000-point level thanks to China’s solid economic recovery and continued policy support, Southwest Securities said in a report. ** The brokerage recommended cyclical firms and companies in the clean energy chain as Beijing pledges “carbon neutralization”. (Reporting by Shanghai Newsroom; Editing by Raju Gopalakrishnan)