Foreign Secretary Lord Cameron has accused the Israeli government of "arbitrarily" blocking humanitarian aid and water from entering the Gaza Strip.

In a letter to Alicia Kearns MP, the chair of the foreign affairs select committee, the foreign secretary said it was "vital" that the number of trucks entering the enclave is increased.

Half the population of Gaza is now at imminent risk of famine amid widespread food shortages, the World Bank warned this week.

Since Israel’s war against Hamas began almost six months ago the number of trucks carrying aid and commercial goods into the territory has dropped from around 500 per day to just 165 on average at the start of March, Lord Cameron wrote.

"It is of enormous frustration that UK aid for Gaza has been routinely held up waiting for Israeli permissions," he said.

"For instance, I am aware of some UK funded aid being stuck at the border for just under three weeks waiting for approval."

Lord Cameron added: "The main blockers remain arbitrary denials by the Government of Israel and lengthy clearance procedures, including multiple screenings and narrow opening windows in daylight hours."

He continued: "I agree with the [foreign affairs] committee that increasing the number of trucks going into Gaza is vital.

“I remain gravely concerned that any aid including UK aid has been stalled, delayed or rejected at the border with Egypt. The Prime Minister and I have raised this consistently with the Government of Israel, including most recently in my meeting with Benny Gantz. I will continue to press this point.”

The distribution of aid within Gaza, meanwhile, has been hindered by Israel preventing staff from getting visas, he added.

“This needs to change,” Lord Cameron wrote. 

"We continue to reiterate to the Government of Israel the need to approve more visas for UN staff and also ensure effective de-confliction mechanisms are in place.”

Earlier this month, Faris Arouri, the director of the Association of International Development Agencies, said that at least 99 humanitarian workers have visas that have already expired or that will expire in the next six months.

Israel’s welfare ministry has claimed that it does not have the ability to assess all applicants for their ties to militant groups.

Kearns wrote to Lord Cameron following a social media spat with Israeli government spokesman Eylon Levy, who has since been reportedly removed from his position.

Earlier this month, Levy claimed on X/Twitter that Israeli authorities had placed no limits on the supply of food, medicine or shelter equipment to Gaza.

"Test us," he added. "Send another 100 trucks a day to Kerem Shalom [border crossing] and we'll get them in."

Writing to Lord Cameron, Kearns asked that the British government take up this offer.

She wrote: “As you can see, the Government of Israel is stating there are no issues getting aid into Gaza.

"This is not the assessment I have reached, nor that of the international aid organisations I have met, nor Governments with whom I have spoken. You have been equally clear in your recent statements and media interviews that Israel can increase the aid deliveries if it chooses to do so.”

Responding, Lord Cameron slapped down a claim made by Levy that the Keren Shalom crossing was closed due to a request from the United Nations.

"In response to the Israeli spokesman claims you quote in your letter, I can confirm that the UN has not requested that the Kerem Shalom crossing is closed on Saturdays,” he wrote. “It is our understanding that Israel closes it due to the Sabbath.”

Israel has also blocked the supply of water to Gaza, Lord Cameron said and could restart it at any time.

“We continue to press Israel to allow in the fuel supplies needed for water pumping and desalination, which met 80 per cent of water needs in Gaza prior to the conflict,” he wrote.

"We are also calling on Israel to restore water through the pipelines from Israel, including into the north where up to 300,000 people remain. Israel has the ability to turn the taps back on-they should do so.”

According to Unicef, at least half of Gaza's water facilities have been destroyed, while according to Unrwa 70 per cent of the population have been reduced to drinking salty or contaminated water to survive.

On Thursday, Tedros Adhanom Ghebreyesus said that recent deliveries of humanitarian supplies by air and sea were welcome but not enough. 

“The future of an entire generation is in serious peril,” he said. “Once again, we ask Israel to open more crossings and accelerate the entry and delivery of water, food, medical supplies and other humanitarian aid into and within Gaza.”