A gang of teenage arsonists who torched the M1 had filmed earlier blazes they had started while singing hit song Your Sex Is On Fire, a court heard.

Some of the group laughed and joked and sang the Kings of Leon track as they watched a blaze they had sparked engulf a Wendy house in Edgewarebury Park, north London, it is alleged.

It was the first of five fires the gang started over a five-day period which included a fire at a scrap yard which closed the M1 for almost a week.

Johno Johnson, 18, of Millfield Road, Edgware, who admitted conspiracy to commit arson in relation to four of the fires but denied involvement in the M1 blaze, filmed and took photos of the gang's handy work.

The jury was today shown a video of the Wendy house burning - a conspiracy which is denied by a 15-year-old from Harrow, a 15-year-old from Edgware, Josh Lambe, 18, of Harcourt Avenue, Edgware, and Damien McQueen, 18, of Harcourt Avenue, Edgware, but admitted by a 17-year-old, from Edgware, and 18-year-old Luke Matthews, of Richmond Court, Hatfield.

As the blaze took hold one of the group could be heard singing "Your sex is on fire” to a background of laughter before one said “This is some serious shit”.

The jury was also shown pictures of members of the group posing next to the burnt out structure which were later found by police posted on Facebook.

James Brown, prosecuting, read text messages between McQueen and Matthews as McQueen was on his way to the first fire they started on April 12.

McQueen boasted he had got: “Screen wash, flammable carpet cleaner, something extremely flammable and a large old curtain.”

To which Matthews replied “Good bro, good”, and McQueen texted back “Don't you love it”.

Earlier in the week, the 17-year-old had looked up on the internet “How to start a fire” and Matthews had plotted with a girl to go to an abandoned house, get drunk in it and set it on fire, the jury heard.

The trial continues.