It’s been saving lives from its base in Marden for more than a quarter of a century – but now the air ambulance looks set to move out of the Weald.

In a shock move, charity bosses say it is no longer a viable site and have applied for permission to build a new base at Rochester Airport, 15 miles away.

If approved, it would mean relocating more than 30 staff from the trust’s management, administration and fundraising teams to a new office block there.

The trust said keeping that team in Kent, the "heart of the organisation", was essential.

It had previously said it was looking to expand the Pattenden Lane base, after proposals to move operations to Paddock Wood fell through.

But now Kent, Surrey and Sussex Air Ambulance Trust wants to relocate to Medway ahead of the arrival of two new helicopters.

The large size of the aircraft and need for them to be available for night flights, which is not possible from Marden, mean the existing base will be unsuitable once they come into operation in the next two years.

The helicopters would be based at its second site in Redhill, but would use Rochester as a forwarding base to allow them to cover the whole of the South East and help patients faster.

The charity relies almost entirely on public donations for the roughly £8 million per year it costs – a figure not lost on villagers in Marden and the wider Weald area, who have organised countless fundraisers over the years.

In 2015, when the trust outlined unsuccessful plans to move its operations to Paddock Wood, chief executive Adrian Bell, said the charity’s heart lay in the Weald, and hoped it could stay there.

Speaking at the time, he said: “This [Paddock Wood] is the best place for us.”

But now a planning statement, on behalf of the trust, says: "The site at Marden has been full to capacity for a number of years.

"It lacks the airside infrastructure and expansion opportunity to be a viable solution as a forward helicopter operating base for larger aircraft for the longer term.

"This applies equally to the office facilities required to meet the needs of a growing charity."

MP for Maidstone and the Weald, Helen Grant, said: "I am a big supporter of the Air Ambulance in Marden.”

“I have now been able to speak to the CEO at Kent Air Ambulance and he has confirmed to me that they are hoping to move to Rochester because they have out grown their site in Marden, which is not big enough for them to operate their two new helicopters arriving in April and October.

"He has assured me that they will be remaining in Kent- ‘that their heart is in Kent and that this is where their routes are’ but he needs to be able to run a sustainable 24 hour service.”

• To view the application visit tinyurl.com/KMairambulance

Kent, Surrey and Sussex Air Ambulance Trust has been eyeing up a new base for around four years.

For the past 25 years the charity has been operating out of Marden and has a second site in Redhill in Surrey, but its helicopters often use satellite airfields, such as Rochester, in bad weather or to carry out maintenance.

Rochester Airport was used around 150 times by the charity last year.

In 2015, after scouring the region, bosses pinned their hopes on an airfield less than three miles away from Marden, in Paddock Wood.

The charity announced it wanted to bring its operations under one roof and close the sites in Pattenden Lane and Redhill, saying running from two locations would eventually push the charity to breaking point.

But the £7.5 million plans to relocate to the Old Hay Airfield off Willow Lane, Paddock Wood, faced a huge backlash.

Paddock Wood Town Council did a dramatic U-turn, voting to object to the plans after initially raising no objections. It came after hearing from disgruntled residents.

Collier Street Parish Council also added its voice to the opposition.

In a six-page letter to planners it cited issues with light and noise pollution, road access, flooding and landscape.

The CPRE said because the airstrip was rarely used, the application represented “a very substantial change of use of a greenfield site”, the highest class of farmland.

The planning application was withdrawn and in June 2016 the trust announced it would be expanding Redhill instead, after a hanger became available there.

The trust said the U-turn had nothing to do with concerns about helicopter noise and the effect on the countryside, but was the most cost-effective way forward.

Bosses said they would apply for planning permission to expand the Marden helipad, and that its headquarters and fundraising base would remain in the Weald.

1989: The air ambulance was launched

1998: The trust was struck by tragedy when one of its helicopters crashed near Burham, killing all three crew members

2000: Kent Air Ambulance Trust moved to a purpose built facility in Marden

2007: The Surrey and Sussex Air Ambulance was launched from Dunsfold Park, on the Surrey/West Sussex border

2013: Kent, Surrey and Sussex Air Ambulance Trust became the first in the country to perform blood transfusions at the scene of emergencies

2013: The first 24-hour air ambulance service was launched after operations were moved from Dunsfold to Redhill

2015: Plans unveiled for single base to replace Redhill and Marden with a site in Paddock Wood

2016: Proposal scrapped and replaced with idea to expand Redhill and Marden

2017: Planning permission sought for move from Marden to Rochester