incumbent on

Brown, a former UK prime minister, said: "It's also incumbent on us to ensure that Nigerian schools are safe spaces for learning, not spaces where children can be plucked from their classroom for criminal profit."

“It’s incumbent on every single one of us to put our best foot forward,” he said.

As the governing party at the time, he added, it was "incumbent on us" to show the party could deliver its policy programme.

She might also be worried about the toll it could take on her political prospects as an incumbent on the ballot when voters turn angry.

"But no matter where you're going in the world, I think it's important for people to remember that it's incumbent on you, the traveller, to engage responsibly with the destination."