Some of the coolest picnic pitches in the city are within the floral borders of famous Kew Gardens. You have to pay to have a look around but it’s totally worth it - especially to have a nosy inside the newly reopened Temperate House, which is stuffed full of impressive rare plants. Once you’ve splurged on entry (£16.50), bringing a picnic will definitely save you some pennies.
Best spot: If you want to nibble au naturel, hunt down the picnic benches in Kew’s woodland areas - they’re lovely.
Need food? Kew Gardens has a few great cafes and restaurants that'll offer takeaway.
Anything else I should know? Kew have gone super green and banned single-use plastic from its cafés and restaurants, and offer discounts if you bring a reusable coffee cup.