LONDON, Nov 4 (Reuters) - British new car registrations dropped by roughly 25% year-on-year in October, according to preliminary industry data released on Thursday, as a lack of semi-conductor chips continued to hit the sector worldwide. The Society of Motor Manufacturers and Traders (SMMT) said it expected total full-year sales to stand at 1.66 million cars, only 1.9% higher than 2020, when COVID-19 lockdowns and restrictions hit the economy. The SMMT will provide the final figures for the month at 0900GMT. (Reporting by Costas Pitas; Editing by Kate Holton)