The meeting comes a day after Israel expanded its attacks on Hamas with an airstrike that targeted the assassination of its political leaders in Qatar, one of Britain's Middle East allies, an attack Starmer condemned.
Earlier on Wednesday, Starmer and Herzog shook hands briefly and unsmilingly on the steps of Downing Street before entering the No. 10 building.
A Downing Street spokesman said Starmer raised the Israeli airstrike on Qatar with Herzog, and condemned the incident as "completely unacceptable." The spokesman added: "(Starmer) said the strikes were a blatant violation of the sovereignty of a key partner and do nothing to secure the peace we all so desperately want."
The spokesman stressed that Starmer told Herzog that Israel must "prevent the worsening famine (in Gaza) by allowing aid in and halting its offensive operations" in the Palestinian enclave.
He added that Starmer also told Herzog that Britain and Israel have been long-standing allies, and that he "will continue his work to ensure lasting peace and a better future for both the Israeli and Palestinian people."
For his part, the Israeli president said that an argument broke out between him and Starmer at the British government headquarters in London on Wednesday during what he described as a "difficult" meeting that addressed deep disagreements regarding their countries' recent behavior.
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The Israeli government was angered by Britain's plan, along with several other Western countries, including France and Canada, to recognize a Palestinian state unless Israel met conditions that included a ceasefire in Gaza.
"Things were raised that were tough and strong, and obviously we can argue, because when allies meet they can argue. We are two democracies," Herzog said in a later meeting at Chatham House.
He added that Starmer's plan for establishing a Palestinian state and his views on humanitarian aid in Gaza were the basis of the dispute, adding that he called on the British government to send a fact-finding mission to Israel, as he put it.
Asked why he met with Herzog, Starmer said: "I will not abandon diplomacy. This is an immature policy."
Wes Streeting, who is health minister in Starmer's government, said this week that Israel's handling of the war in Gaza was leading it to "pariah status."
Britain had promised to recognize a Palestinian state before the UN General Assembly this month unless Israel met four conditions, including ending the war in Gaza and allowing more aid into the Palestinian enclave.
