Margate on the Kent coast, 90 minutes from St Pancras, the seaside town reopened post-2010 by the Turner Contemporary; The Sett, Buoy and Oyster, and Sargasso run serious seafood-focused kitchens.
Tip: Visit Saturday for the Turner Contemporary and lunch at The Sett. The Old Town fish-and-chip counters run from 11:00 on the seafront.
Oxford, an hour from Paddington, runs historic university pubs (The Turf Tavern from 1381, The Eagle and Child) and the Covered Market for traditional British lunches.
Tip: Sunday roast at The Magdalen Arms is the canonical pub lunch in town. Walking tour of the colleges fills a morning before lunch.
Cambridge, an hour from King's Cross, runs Fitzbillies's century-old Chelsea bun bakery (1920), Midsummer House two-Michelin-star riverside dining and the punting-and-lunch combination.
Tip: Punting on the Cam in summer paired with lunch at The Cambridge Chop House is the canonical day. Fitzbillies for Chelsea buns and morning coffee.
Rye in East Sussex, 90 minutes from St Pancras, the medieval Cinque Ports town runs The Mermaid Inn (1420), Webbe's Fish Cafe and the cobbled-street tea-rooms of Mermaid Street.
Tip: Visit weekdays to skip the weekend crowds; the antique market runs every Tuesday. Webbe's books a fortnight ahead for weekend lunch.
Brighton on the south coast, an hour from Victoria, runs The Salt Room beachfront dining, The Lanes' twisted alleys of fish-and-chip shops and the Royal Pavilion's Indian-themed lunches.
Tip: Visit a Saturday for the Beach Box food carts on the seafront. Sundays at Petit Pois in The Lanes for the small-plates lunch.
Whitstable in Kent, a 90-minute train ride from London, runs The Whitstable Oyster Company since 1856, Wheelers Oyster Bar from 1856 and a fishing-village seafront. Oysters at the beach.
Tip: The Whitstable Oyster Festival runs the last weekend of July; book lunch a fortnight ahead. Visit October to April for native oyster season.
Bray on the Thames in Berkshire, 45 minutes from Paddington, runs Heston Blumenthal's three-starred Fat Duck and the Hinds Head pub. The Riverside Brasserie at Bray Marina is the cheaper option.
Tip: Fat Duck booking opens three months ahead and sells out in minutes. Lunch at the Hinds Head Sunday roast is the easier visit at £40.