A number of flares and explosive devices were found concealed inside the toilets at the stadium as well as a rucksack full of pyrotechnics discovered in nearby Brompton Cemetery, Kensington.
Inspector Matt Ashmead from the Met's Central Football Unit said: "Several devices were let off inside the away end at Stamford Bridge on Saturday and officers seized a number of other devices on the day as well.
"Flares and pyrotechnic devices inside stadia are very dangerous and they can reach extremely high temperatures.
"There is a very good reason that they are banned from football matches, as they can cause horrific injuries and can also be frightening for the many young fans that attend matches.
"Some fans might think that setting off a flare is a good way to support your team, but it is putting yourself and fellow fans at risk. Bringing flares to football matches is completely unacceptable and you can expect to be arrested and charged if you are caught in possession of such a device."
Five men were arrested, aged between 18 to 31, by officers policing the match, including two arrests for possession of a flare.
The following arrests were made before, during or after the match:
- A 31-year-old man has been charged with possession of a flare after he was arrested during the match;
- An 18-year-old man of Sidcup, Bexley who was arrested on suspicion of possessing Class A drugs accepted a caution;
- A 27-year-old man of South Norwood, London who was arrested on suspicion of possessing Class A drugs accepted a caution;
- A 24-year-old man who arrested on suspicion of possession of a flare has been released on bail until mid-May pending further enquiries;
- A 19-year-old man who was arrested on suspicion of assault and possessing Class A drugs has been released on bail until mid-May pending further enquiries
Officers continue to review footage from the match to identify any other individuals involved.
Anyone with information should contact the Central Football Unit via 101, or tweet @MetCC.
To give information anonymously visit Crimestoppers or call on 0800 555 111.
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