LONDON, Oct 13 (Reuters) - Britain’s economy grew 0.4% in August, leaving it just 0.8% smaller than it was in February 2020, just before the country went into its first COVID-19 lockdown, the Office for National Statistics said on Wednesday. Economists polled by Reuters had forecast monthly gross domestic product growth of 0.5% for August. (Reporting by David Milliken, Editing by Alistair Smout) Our Standards: The Thomson Reuters Trust Principles.