The military is helping to deliver fuel to forecourts as a body representing petrol retailers described a “marked improvement” in the situation across most of the country.

London and the South East have only see a “marginal” improvement, with these areas still facing a “challenging” time, the Petrol Retailers Association (PRA) said.

The organisation said its survey of a quarter of all independent petrol stations in Great Britain on Monday morning showed that around a fifth of these sites around London and the South East remained without fuel.

When it comes to the rest of the country that figure was 8%, said the PRA, adding that 86% of sites surveyed have both petrol and diesel available.

The association represents independent forecourts across the UK and works with around 80% of all motorway services areas.

Gordon Balmer, executive director of the PRA, said it is “grateful” that the Government has brought in military drivers to make deliveries but called for more action to address “the needs of disproportionately affected areas”.

He said: “Today’s figures show the situation is still challenging around London and the South East despite a marginal improvement: 62% of the sites surveyed have both grades of fuel (petrol and diesel) available, 18% have only one grade and 20% are dry.

“Across the rest of the country, however, there has been a marked improvement since yesterday with 86% of sites having both grades of fuel thanks to steady deliveries and stabilising demand, 6% having only one grade and 8% being dry.

“We are grateful for the support lent by the Government through their provision of military drivers, although further action must be taken to address the needs of disproportionately affected areas”.

Members of the armed forces arrived at the Buncefield oil depot in Hemel Hempstead on Monday to help deliver fuel, with soldiers – in uniform and wearing face masks – seen walking near the gates to the Hertfordshire Oil Storage Terminal.

It is understood almost 200 military personnel were due to be deployed from Monday, including 100 drivers.

By the end of this week it is expected that 150 crews will be delivering fuel across the UK.

The majority of the first tranche of military personnel are being deployed to terminals that service London and the South East, targeting the areas most in need of support.

Payments for military support are understood to be commercially sensitive.

In a further sign of an improving situation, forecourt operator EG Group announced on Monday that it would remove the £30 cap on fuel sales.

A spokesperson said: “Following a significant improvement in fuel availability at our sites, with customer purchasing behaviour returning to normal levels in the majority of locations, we are pleased to confirm that we can now remove the £30 cap on buying fuel.”

They added that there remains “some challenges, primarily in our locations in the South and the South East, but following the actions from the Government to secure additional drivers from the military this week, we expect availability issues easing in the coming days.”