“We call BS,” González said of politicians who refused to act on gun violence. “If you actively do nothing people continually end up dead so it's time to start doing something.”

Marjory Stoneman Douglas was the latest US school shooting with double digit deaths. In 2012, 20 first graders and six school staff members were murdered by a lone gunman at Sandy Hook Elementary School in Connecticut.

In 2007, 32 students and a teacher were killed at Virginia Tech university by another lone gunman.

In the past six months 58 people were also killed by a gunman in Las Vegas and 26 people were killed in a shooting at a Texas church.

Student journalists from the Eagle Eye, the Marjory Stoneman Douglas school newspaper, published a manifesto on Friday calling for law changes that included a ban on semi-automatic weapons that fire high-velocity rounds, a ban on gun accessories that simulate automatic weapons, and a call to address links between shootings and mental health.

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March for Our Lives raised $4 million from an online crowdfunding campaign while George and Amal Clooney, Steven Spielberg, and Oprah Winfrey were among celebrities to have provided significant financial support to the teenagers.

“We cannot allow one more child to be shot at school,” reads the mission statement on the March of Our Lives website.

With active shooter drills the norm in American schools, Stoneman student Kasky has called his peers "the mass-shooting generation".

It’s not just politicians who March for Our Lives want spotlighted. The political influence of the National Rifle Association is also an issue, according to students.

The NRA has pushed back hard against March for Our Lives with one spokesman saying school football coach Aaron Feis, killed in the latest attack, would have lived if he was carrying an AR-15 military -style weapon in class “instead of his empty hands”.

“You people want a culture war but the culture isn’t on your side,” said NRA spokesperson Collins Idehen, who uses the pseudonym Colion Noir for TV shows hosted on the NRA’s website.

Organisers want to use the weekend events to register first-time voters and make gun control a sustaining political issue - beginning with this November's midterm elections.

“Your legacy is gone,” #NeverAgain co-founder David Hogg warned politicians. “If you don’t stand up with us now, you’ll be standing against us.”