River Thames users have been urged to take care after more than 500 razor blades were found dumped in the water.
The discovery, made by a member of the public on the foreshore in the Isleworth area of west London, came as a group of schoolchildren were taking part in a wildlife project nearby.
While most of the blades have now been collected there may be some still out there, Jon Beckett from the Port of London Authority warned.
"We are advising river users and members of the public generally to take extra care when they are near the foreshore of the Thames in this area.
"Although it appears that we've collected most of them, some may be hidden in the mud. Because this is a fast flowing tidal river some are no doubt already elsewhere in the river.
"If anyone finds something as dangerous as this, on or in the river, they should contact the Port of London Authority."
Jason Davey, from Berkshire, who discovered the blades as he walked along the foreshore said he warned the teacher in charge of the school group to keep the children out of harm's way.
"I couldn't believe it to be honest. I looked down and saw all these razor blades. I've no idea what was going through the mind of whoever did this," he said.
Best days out in London this summer
River Thames warning as 500 razor blades found dumped
London’s Chinatown is hosting its first ever Family Day festival on Sunday 27 July. The area’s famous streets will welcome an exciting array of entertainment and activities for children of all ages throughout the day. Two stages will form the focal points of a range of traditional Chinese acts, martial arts and a gravity-defying cube spinning display. Dotted around the streets will be Chinese magicians, jugglers and stilt walkers along with Shaolin warrior monks and moving statues.
To celebrate the fly-fishing season and encourage the great British public to enjoy the outdoors, Orvis is hosting free fly-fishing courses for beginners at its flagship store on Regent Street. Participants will be under the instruction of Orvis’ renowned fishing specialists or 'ghillies'. During the two-hour session you will learn the basics of fly-fishing and fly-casting. Courses run until October 2014. The fly-fishing courses are the perfect excuse to enjoy the outdoors with all the family and have fun this summer.
Haven't taken your kids for a ride on the cable car yet? The Emirates Air Line is the first urban cable car in the UK, stretching across the Thames between the Greenwich Peninsula (South) and the Royal Docks (North). Spanning just over 1km, it takes around 10 minutes to cross and offers unique views of the city (and an affordable experience the kids will love). Passengers can enjoy spectacular views of the city including St Paul’s Cathedral, the Gherkin, Thames Barrier, Maritime Greenwich and the Olympic Park as you fly 90 metres above the River Thames.
Blue Ribbon Village is two days of fantastic, free activities for tots to teenagers at Potters Fields Park in the shadow of Tower Bridge and beside City Hall, taking place from 13 to 14 September. It includes everything from festival music to arts and crafts. The annual event, part of Totally Thames, also brings together scores of voluntary and charitable organisations involved with the ecology, history and industries of the Thames.
The London Dungeon is hosting a Summer Carnivale from 26 July to 31 August, with showmanship, spectacle and plenty of scary fun as the attraction presents its very own carnival starring a cast of colourful characters ready to amaze and astound. Roll up, roll up as the show begins with the Dungeon's Victorian 'Barkers' announcing the mesmerising entertainment inside - from the amazing 'knife throwing' torturer to the discombobulating Hall of Mirrors. Guests can test their strength lifting strong man dumb bells or on the High Striker - will they be as weak as a plague victim or as strong as an axe-wielding executioner? Then look into the future with a fortune card dealt out by the Dungeon's flea-infested fortune teller – and watch out for the resident cockroaches and rats in their colourful carnival-themed lairs. Once inside, there are 18 shows plus two riveting rides to enjoy as 1000 years of London's murky past is brought to life with a special carnival twist. Marvel at Mrs Lovett and her fabulous pies, escape the clutches of Sweeney Todd, meet an escapologist whose enthusiasm knows no bounds and attend the trial of the hirsute bearded lady.
Families visiting London's ArcelorMittal Orbit in the Queen Elizabeth Olympic Park from 24 July and 31 August will be able to engage in a range of daily activities curated by visual artist and art educator Natalie Ryde (previously artist in residence at Kensington Palace and art educator at Hampton Court). Using the ArcelorMittal Orbit as inspiration, kids of all ages will be shown how to use their imagination with a variety of methods from cutting out, sketching, painting and building - whether it’s sketching the London skyline or making their very own ArcelorMittal Orbit. Activities will take place from 2-4pm each day of the school summer holidays and will be included in the entry price.
This summer, Battersea Power Station is hosting a pop-up experience like no other from 10 July to 31 August. Street Feast, London’s finest food, drink and party people, will bring some of the best food traders from across London, including Le Bun, Spit & Roast, Popdogs, Mama’s Jerk and Anna Maes. There will be lots going on, including the best films from Everyman, and visitors can choose from bespoke two or four person pods with waiter service included, comfortable bean bags under the sun or simply soak up the atmosphere with general admission tickets available each day.
Families can get creative in the gardens at Dulwich Picture Gallery at the weekly Art in the Garden sessions. The creative workshops are a great way for children of all ages to get arty outdoors. You can bring a picnic, sit on the lawn and watch the artwork grow.
Formerly an empty rooftop car park, Roof East is a new open-air urban haven for those seeking great food, a classic film or to simply enjoy a beer or ice cold cocktail while watching the sunset over the city and Queen Elizabeth Olympic Park. Located in the heart of Stratford, opposite Stratford Station and Westfield Shopping Centre, the rooftop venue will play host to a wide range of cultural events from plays to dance performances as well as family activities during the school holidays. Up to September, The Rooftop Film Club will also be showing a variety of modern and classic films at Roof East every Tuesday to Saturday and Roof East’s resident bar The Pearl, will open every Tuesday to Sunday, serving drinks and food.
Treat the kids to a day out at Buckingham Palace to see special exhibition Royal Children from 26 July to 28 September. From well-loved toys and treasured family gifts to tiny childhood outfits, the exhibition will give an unprecedented glimpse into life as a young member of the royal family growing up at Buckingham Palace. The exhibition will bring together both family and official gifts presented to royal children, as well as displaying many outfits and toys, including the Queen’s favourite rocking horse as a child. The silk-satin and lace christening robe worn by Prince George, a replica of the original royal christening robe commissioned by Queen Victoria will also be shown.
From 9 to 10 August, cycling event Prudential RideLondon returns after a brilliantly successful first year in 2013. The two-day cycling festival will allow families and amateur riders to take part, as well as attracting the world's best elite cyclists. There will be fun rides for cyclists of all ages and abilities who want to enjoy the fun of cycling in a traffic-free environment. The route will pass many of Central London's famous landmarks. The 100-mile race will appeal to the world's top elite cyclists and amateur cyclists alike, starting at Queen Elizabeth Olympic Park, taking in roads in London and Surrey and finishing in Central London.
More than 5,000 children and their families from all over London will come together to discover the fantastic mix of buildings and spaces the Square Mile has to offer at Archikids. Activities range from workshops and tours, to competitions and DIY events, which makes this a must-do for all the family. Highlights of the two-day festival from 26 to 27 July include On your Scooter trails, the City of a Thousand Architects workshop and Birds Eye Building explorations.