The Yemeni capital of Sanaa, which is around 300km from Hodeida has been hit by airstrikes in recent weeks. (Picture: Xinhua/Mohammed Mohammed).
A Saudi-led coalition backing Yemen's exiled government has started an assault on Yemen's port city of Hodeida.
Aid agencies have warned the three-year conflict could cause even greater problems for the Arab world's poorest country.
More than 10,000 people have been killed in Yemen's civil war. The Saudi-led coalition has previously been criticised for its airstrikes killing civilians.
In 2017, the High Court ruled the sale of arms sales to Saudi Arabia from the UK were lawful after seeing secret documents, amid campaigns from activists against the sales.
Members of the Royal Air Force are currently deployed to Saudi Arabia giving support to Royal Saudi Air Force aircrew. Twenty-six British military personnel were on secondment in the country last year.
When asked about the UK's role in the loading and maintenance of weapons for Saudi aircraft participating in operations in Yemen since 2015, Defence Minister Guto Bebb MP replied:
"UK-contracted personnel, including UK military personnel on secondment to BAE Systems, support the safe storage and issue of weapons in accordance with long-standing government-to-government arrangements.
"They do not load weapons for operations in Yemen."
Earlier this year, it was announced that Saudi Arabia agreed a preliminary deal to buy 48 Typhoon jets from the UK.
According to videos posted on social media, convoys of vehicles appeared to be heading towards the rebel city on the Red Sea. Heavy gunfire could clearly be heard in the background.
Saudi-owned satellite news channels said the battle had begun, citing military sources. State media in both Saudi Arabia and the United Arab Emirates did not immediately acknowledge the assault.
Forces loyal to Yemen's exiled government had neared Hodeida in recent days, along with irregular fighters led by Emirati troops.
The port is some 90 miles south-west of Sanna, Yemen's capital held by Shiite rebels known as 'Houthis'.
Emirati Minister of State for Foreign Affairs Anwar Gargash earlier told French newspaper Le Figaro the deadline for a withdrawal from Hodeida by the Houthis expired early on Wednesday morning.
The United Nations (UN) and other aid groups had removed their international staff from Hodeida ahead of the rumoured assault.
The UN and Western nations say Iran has supplied the Houthis with weapons from assault rifles up to the ballistic missiles they have fired deep into Saudi Arabia, including at the capital, Riyadh.
Before the war, over 70% of Yemen's food and fuel imports came through Hodeida, accounting for over 40% of the nation's customs income.
The port remains important for imported aid, food and medicine for a nation driven to the brink of famine by the conflict and a Saudi-led blockade.
The UN says some 600,000 people live in and around Hodeida, and "as many as 250,000 people may lose everything - even their lives" in the assault.