Seventeen British nationals, including children, are feared dead or missing after the Hamas attack on Israel on Saturday, an official UK source has told the BBC.

The previous estimate for the number of dead or missing was put at “more than 10”.The death toll in Israel has reached 1,200, with more than 900 people killed by Israeli air strikes on Gaza.

The deaths of Nathanel Young and Bernard Cowan have been confirmed.

Mr Young was a 20-year-old who attended JFS School, a Jewish school in North London, and was serving in the military in Israel.

Bernard Cowan grew up in Glasgow before settling in Israel with his wife and three children.

The family of Daniel Darlington have also said they believe he is among those killed.In a statement posted on Instagram, his sister referred to him as Danny and her “baby brother”. She said he was killed at the Nir Oz kibbutz alongside a friend.

Jake Marlowe was working as a security guard at the Supernova music festival, where 260 people were killed when it was stormed by militants.

The 26-year-old has been reported as missing after the attack, which took place at the Re’im kibbutz around 3.7 miles (6km) from the Gaza barrier.

He was also a former pupil of JFS in North London.

Speaking to BBC Breakfast on Wednesday, Defence Secretary Grant Shapps said the UK is offering “moral” as well as “practical support” to Israel.

He said he had spoken to ministers in the Israeli government.”We have asked the Israeli government to let us know what they need. And again, we continue to talk to them about that.”