"We want to have a grown up, honest conversation with all union leaders about what is responsible, what is reasonable and what is affordable for our country when it comes to pay," Sunak said, speaking to reporters during a visit to a school in London.

"We think that those conversations should happen. That's why we've invited everyone in to have those talks on Monday and I'm hopeful that those talks can be constructive."

(Reporting by William James, writing by Sachin Ravikumar, Editing by Kylie MacLellan)