Tucked behind Charing Cross Road, this is a super spot for a leafy lunchtime break. The plants, flowers and wildlife in the garden are all maintained by volunteers. Look out for frogs and sparrows, which are thriving thanks to an enthusiastic conservation initiative. After exploring, pop into the nearby churchyard of St Giles in the Fields for weekly food stalls and delicious coffee from Rosie & Joe’s Coffee Stall.

A short walk from St Paul’s Cathedral lies one of London’s most touching monuments: George Frederic Watts’s ‘Memorial to Heroic Self-Sacrifice’. Within the quiet Postman’s Park, nestled beneath a tiled roof, are just over 50 ceramic plaques, each commemorating an ordinary person who lost their life trying to save others. Many of the descriptions are truly heartbreaking, and you can easily spend an entire lunchbreak contemplating their selflessness.

Tucked away in Abney Park, you'll find Abney Park Cemetary, where Salvation Army's founders are buried, among others. Creep through the overgrown woods of the cemetery, past the crumbling gravestones, and you will eventually emerge into a large central clearing dominated by the menacing shell of a derelict chapel. The impressive gothic-revival building dates from 1840, but was gutted by fire in the 1970s and closed.

Barnsbury Wood was once the garden of George Thornhill, who built the surrounding houses in the 1840s. But stroll through the wood to find the real hidden gem here, its nature reserve, which is the smallest in London. Snuck between houses in affluent Barnsbury it was originally a vicarage garden. After being abandoned in the 1840s a woodland naturally grew and the Barnsbury Wood is now home to the sixteen spot ladybird. Please note: dogs are not allowed.

Thousands wander across Hampstead Heath's wild and undulating parkland every year, but very few discover this eerie and elegant pocket of faded grandeur on the West Heath. Built by Lord Leverhulme at the start of the twentieth century as a setting for his extravagant parties, it includes impressive gardens and a dramatic elevated walkway, where overhanging plants create a lush canopy and tangled roots twist around smooth stone columns. A little window into the world of the Edwardian super-rich.

Across the road from the better-known Highgate Wood, there is something more magical and quiet about Queen’s Wood – witness its hilly pathways through the oak, beech, mountain ash and cherry trees. It might be only a few hundred metres from Highgate tube station, but native bluebells, wood anemone and countless species of small animals and creepy crawlies make this a wonderful retreat.

Between the generous expanse of Hampstead Heath and the bustle of Royal Free Hospital is a small garden with noble ambitions. The World Peace Garden actually does live up to its name. It's a really peaceful woodland glade with three ponds and a wishing well, making it a perfect spot for some quiet meditation. Residents and traders are responsible for rescuing what had been a wasteground area alongside Hampstead Railway Station for over a century - their words are immortalised on the walls.

Brockwell Park is no hidden gem to Londoners, but its secret walled garden is much lesser known. Four unassuming walls near the western edge of Brockwell Park enclose one of the most enchanting – and perhaps only – respites from the buzz of Brixton. The urban clamour melts away as you meander along stone pathways, between beds of vibrant plants and flowers, to discover bubbling fountains and secluded benches. This was once the kitchen garden for Brockwell Hall, but is now an oasis of calm.

You know Crystal Palace Park, but have you discovered its maze yet? This network of head-scratching hedgerows is almost as old as the dinosaurs – the Crystal Palace dinosaur sculptures, that is (had you going there, didn't we?). Dating from around 1870, the puzzle is tucked away near the park's northern lake. After falling into disrepair, it was renovated in 2009 to commemorate the centenary of the Girl Guides.

Walk through Mordern Hall and an ancient mill, where Kingfishers perch on reeds by the riverbank, and an old-fashioned waterwheel is slowly turned by the gentle current. It sounds more like an idyllic country village than a public space just a few minutes’ walk from the Northern line, but therein lies the charm of Morden Hall Park. Once the sprawling estate of a wealthy family, it's still home to watermills that used to grind tobacco into snuff.