Stop for a pint of local beer (optional) at the Lamb & Flag pub in Covent Garden. Once know as the 'bucket of blood' due to its connect with bare-knuckle boxing, the pub is older than the USA and a favourite with locals.
The pub offer a selection of seasonal craft beers and soft drinks which can be purchased direct. Alternatively, if you'd rather take a break in Covent Garden Market that is also possible.