An investigation has been launched by the Met's Central Football Unit after several flares, 'smoke bombs' and 'thunderflash' pyrotechnics were set off during the Chelsea v Crystal Palace match.

Five people were arrested at the match, played at Stamford Bridge on Saturday, April 1, including two arrests for possession of a flare.

Officers also found a number of flares and pyrotechnic devices hidden inside toilets at the stadium and a rucksack full of pyrotechnics that was found in nearby Brompton Cemetery.

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."

Officers are looking at footage from the match to identify any other individuals involved in setting off pyrotechnic devices.

Anyone with information can contact the Central Football Unit via 101, or by tweeting @MetCC.

To give information anonymously call Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.

Five men were arrested 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 from Sidcup who was arrested on suspicion of possessing Class A drugs accepted a caution.

A 27-year-old man from South Norwood 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.