SHADES OF MARGARET THATCHER.

LONDON • Britain’s new prime minister, Theresa May, has again confounded expectations.

When she stood up at the dispatch box for her first prime minister’s questions on Wednesday, not many expected May — often described as a cautious, pragmatic politician — to let it rip during the high-profile weekly contest in the House of Commons.

But as we saw from her first hours in power, she didn’t hold back.

In one of the most striking moments, she mocked embattled Labour party Leader Jeremy Corbyn. The majority of Labour MPs have voted to say they don’t have confidence in his leadership, but Corbyn has said he has no intention of resigning, arguing that he has the overwhelming support of Labour party members.

“I suspect that there are many members on the opposition benches who might be familiar with an unscrupulous boss. A boss who doesn’t listen to his workers. A boss who requires some of his workers to double their workload, and maybe even a boss who exploits the rules to further his own career.” Ouch. If that wasn’t enough to make her own party go wild with glee, May also showed shades of former prime minister Margaret Thatcher when she planted an elbow on the dispatch box and intoned in a deeper-than-normal voice, “Remind him of anybody?”

“I know this is very funny for all Conservative members,” Corbyn said. “But I do not suppose too many Conservative MPs have to go to a food bank in order to supplement their family table.”

Prime minister’s questions is a chance for MPs to hold the prime minister to account, but it’s also a chance for party leaders to boost morale in their ranks.

Judging by the shouts of “More! More!” from the Tory benches, May cleaned up.

They cheered like giddy schoolchildren when she ridiculed the Labour party for not producing a female prime minister when the Conservative party has now had two.

“In my years here in this house, I’ve long heard the Labour party asking what the Conservative party does for women. Well, it just keeps making us prime minister,” she said.

But while she delivered the zingers, many of them possibly well-rehearsed, she also evaded several questions. She dodged a question asking her to comment on some of the controversial remarks made over the years by Foreign Secretary Boris Johnson, including his views on President Obama’s “partKenyan” heritage. And when asked to rule out the United Kingdom’s seeking access to the European Union’s single market in upcoming negotiations with the bloc, she did no such thing.

By all accounts, it was a confident debut. Before becoming prime minister, May was Britain’s home secretary and often sat on the green benches close to the dispatch box during PMQs.

Clearly, she spent her time watching carefully.