The Government will face a general strike in education if it fails to end the dispute with teachers, a union has warned.

Daniel Kebede, general secretary-elect of the National Education Union (NEU), told thousands of striking teachers on stage at Parliament Square, in Westminster, to “get ready” for a general strike.

He said: “If this Government doesn’t deliver there will be a general strike in education. Get ready now.

“It’s not going to be easy, and it will get harder, but we will win because we have justice on our side… your action will continue to move this Government.”

Teachers across England took part in the rally in Westminster on Wednesday, calling for better pay and more school funding.

They chanted “Oh Rishi, you’re so tight, you make us strike”, held placards labelled “I’d glue myself to this street but I’m out of pritt-sticks”, and booed while passing the Department for Education.

Mr Kebede was joined on stage by Labour MPs John McDonnell and Richard Burgon.

Mr McDonnell said: “Labour MPs need to be on every picket line possible.”

Mr Burgon said: “There’s a whole range of wealth taxes on the very super-rich that could easily fund a properly funded school system.

“As a modest proposal, a 1.5% tax on assets above £10 million will raise more than enough that we need to settle these disputes.”

Primary school teacher Aaron Connor told the PA news agency that teachers need a more effective way to strike.

“Let’s have one hard hit… I’m saying take these five days we’re striking over the course of the year and have them together one after the other,” Mr Connor said.

“To send out a clear message that we’re serious about taking on the Government and serious about having a fully funded education programme.

“We’re not necessarily saying strike more, we’re saying strike clever.”

Two secondary school teachers told PA that the UK Government has “chronically” underfunded their schools, forcing them to “regularly” use their own money to obtain the equipment needed for the school year.

Megan Oliver, 24, an art teacher from Maida Vale, said: “All of our colleagues here have to pay out of our own pocket, while not getting paid enough, to provide equipment, papers, pencils and glue sticks because our schools don’t have enough funding.

“It’s having a knock-on effect on education because we can’t afford equipment – students won’t be able to do certain tasks essential to their learning.”

Oscar Reed, 27, a media teacher from Camden, said: “In media, we don’t have money to buy the specialist equipment we need, so I’ve had to use my own to teach and provide the basic level of content that’s expected.

“School funding is not up to standard, that’s why it’s a joke.”