The number of passengers travelling through Heathrow last month fell as the Middle East conflict continued to disrupt travel.

The airport said passenger numbers fell to 6.7million last month, a 5 per cent drop from last year, as flights were cancelled and travellers pressed pause on booking trips.

The number of transfer passengers continued to increase in April, rising 10 per cent year-on-year, as travellers rerouting to Asia and Oceania switched to Heathrow instead of Dubai and Doha.

Despite the uncertainty, Heathrow boss Thomas Woldbye said demand remained strong with 'current fuel supplies stable,' adding that April was 'still our busiest month so far this year.'

Heathrow said it would provide an updated annual passenger forecast next month.

It comes amid growing uncertainty over jet fuel supply, which has sent prices soaring and led to thousands of cancelled flights.

Airlines have been given the green light to cancel or consolidate flights this summer to conserve fuel and avoid major disruption.

'Heathrow is counting on this being a short-term disruption, but with jet fuel issues becoming a headache for countries around the world, it could turn into a medium-term problem, especially if more holidaymakers delay booking trips,' said Susannah Streeter, chief investment strategist at Wealth Club.

Hopes of a swift end to the war and the opening of the Strait of Hormuz were dashed again overnight. 

Donald Trump dismissed Iran's response to the latest attempt by the US to end the war as 'totally unacceptable', sending the price of Brent crude to around $103 a barrel.

It came as Saudi Aramco joined other oil giants in warning that unless shipping in the Strait of Hormuz resumes, pressure on fuel supplies could stretch into 2027.

Last week, British Airways owner IAG warned that if the current conflict continued to restrict flows of both crude oil and jet fuel, 'there is the potential for supplies of jet fuel to be restricted on a global basis.'