Pro-Israeli demonstrators chant slogans in front of a line of police officers during a demonstration in support of Israel outside the Israeli Embassy in London this week. (Justin Tallis/AFP/Getty Images)

As a proposed 72-hour cease-fire failed Friday, reports emerged that Gaza militants had captured an Israeli soldier. For Israel, this would certainly be a big deal. The last Israeli soldier caught by Hamas was Gilad Shalit, who was imprisoned for five years before finally being released in exchange for 1,027 Palestinians. As my colleague Ishaan Tharoor noted recently, for Hamas, capturing Israeli soldiers could be a game-changer in an asymmetrical conflict.

But there's another big factor at play here: According to the United Kingdom's Channel 4 News, the captured soldier is a 23-year-old British-Israeli citizen, Lt. Hadar Goldin.

So far, the British government hasn't confirmed Goldin's nationality (U.K. Foreign Secretary Philip Hammond told the BBC he had "no information" that said the kidnapped soldier was British). If it does turn out to be true, it may put Britain's awkward relationship with Israel under fresh scrutiny.

Diplomatically, Britain is an important ally for Israel. Historically, the colonial-era British Mandate of Palestine eventually led to the formation of a Jewish state, and just a few months ago, Prime Minister David Cameron told the Knesset that his belief in Israel was "unbreakable." For the general public, however, the relationship between the two countries is far more complicated. A BBC World Service poll conducted earlier this year found that just 14 percent of the British public had a positive view of Israel's influence; 72 percent viewed it negatively. And while the United Kingdom hasn't seen the more virulent anti-Israel protests that shook France and Germany recently, London has seen as many as 45,000 people march on the Israeli Embassy in recent days. In part, protesters were angry at Britain's support of Israel at the United Nations and repeated arms deals between the two nations.

There are many complicated reasons for the British public's distrust of Israel: Some might put it down to the country's large Islamic community, others would argue that lingering anti-Semitism colors the British viewpoint. But the capture of a British-Israeli soldier would present a special issue. At the very least, for the British it's a reminder that there are quite a large number of British soldiers serving in the Israel Defense Force (Robert Fisk of the Independent recently wondered, provocatively, if any could have been involved in war crimes).

If a British-Israeli soldier has been captured, it may also affect how Hamas deals with the situation. The Palestinian militant group is acutely aware of how it is perceived around the world, and that perception played an important role in the release of kidnapped BBC journalist Alan Johnson a few years ago. Would it be willing to risk alienating British support?

The legal requirement for Israeli citizens to serve in the military, plus the unique character of Israeli nationality, mean that dual-nationality soldiers are a factor of life for the IDF – there are believed to be more than 4,000 serving IDF troops who were born outside of Israel, for example. It's also another way in which the conflict in Gaza can have global repercussions, as the United States knows well: Two U.S. citizens have already been killed fighting for Israel.