Why is Holme Fen wildfire lasting days?

Firefighters are continuing to tackle a large blaze at a nature reserve in the Cambridgeshire Fens. As it enters its fourth day, how long could the fire go on for and why is it so hard to tackle?

Holme Fen is a peatland nature reserve between Peterborough and Ramsey in Cambridgeshire.

The sprawling Natural England-managed site is 2.75m (9ft) below sea level and the lowest land point in Great Britain.

It used to be the site of Whittlesey Mere, once the largest lake in southern England.

In the 1850s, it was drained to create farmland.

This became Holme Fen and survives as one of the only fragments of ancient wild fen, along with Wicken Fen on the other side of Cambridgeshire, run by the National Trust.

The site is a haven to such a variety of wildlife that it has been designated as a Site of Special Scientific Interest (SSSI), thanks to more than 500 types of fungi, a birch woodland, an ancient bog, heathland and beautiful birds, including the Eurasian siskin, nightingale and lesser redpoll.

According to the Woodland Trust, an SSSI gives sites more protection than other designations like Areas of Outstanding Natural Beauty.

The status means landowners must manage the site appropriately to conserve its special features.

Holme Fen National Nature Reserve is next to the main railway line between London and Edinburgh, with the nearest train station located at Peterborough.

The habitat spans about 660 acres (270 hectares) – roughly the equivalent of 375 Premier League football pitches.

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Firefighters have been tackling a blaze at Holme Fen since about 10:30 BST on Saturday.

More than 80 firefighters were at the scene on Sunday evening and 14 appliances remained there on Monday afternoon.

Crews from further afield – including Norfolk, Northamptonshire, Hertfordshire, and Bedfordshire - have been helping their Cambridgeshire colleagues.

Firefighters from the county had recently travelled themselves to help the effort to contain a major fire incident at Dunwich Heath in Suffolk.

Personnel from as far away as Merseyside are also due to help at Holme Fen in the coming days - with the site hit by two blazes in less than two weeks.

Cambridgeshire Fire and Rescue Service says it has the current fire surrounded and urged people to stay away from the area.

Incident commander Vicky Best says the service is planning to stay at Holme Fen until at least the end of this week.

The cause of the blaze has not yet been established.

Best says crews are working in very hot conditions and that trees have been falling down around them.

Peat fires can be a struggle to deal with as they can travel undetected several metres underground.

More than 40 firefighters first attended the site on 27 July to tackle the separate blaze, which the fire service said was "deep-seated in peat", making it likely to burn for longer.

Crews were stood down four days later on 31 July.

The fire is believed to have been started deliberately, with Cambridgeshire Police investigating how it started.

At the time, the fire service's incident commander Nev Burgess told the BBC: "My previous experience is that these do tend to last for days as opposed to hours because of the type of fire that they are and the access we need."

It was "incredibly difficult" to know the exact location of peat fires "because it burns under the surface and it burns quite fiercely", he added.

On Sunday, Suffolk Fire and Rescue Service said underground temperatures at parts of Dunwich Heath, which includes sections of peat, had reached 600C (1,112F).

The Suffolk wildfire broke out on 29 July and the major incident there was stood down on Monday, 12 days later.

Despite its proximity to the railway, a Network Rail spokesperson said on Monday the fire was having "no operation impact at present", adding it was monitoring the situation.

Mark Whittington, landlord of the nearby Admiral Wells pub, says the "commotion" in the area was unusual.

"It's such a sad sight, though, when you look over the railway track and see all the beautiful peat woodland there that's been there a long while," he says.

BBC journalist John Devine reported from the scene on Monday and told how he could see thick plumes of smoke billowing from about 10 miles (16km) away as he travelled there.

"When you approach the place, the smell really gets into your car. You can smell it from miles away," he says.

"It's a bit like driving through mist or fog."

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