
Two men have been arrested following an explosion at an alleged 'cannabis factory' at a block of flats which saw more than 70 firefighters tackle a huge blaze.

Police confirmed then men were in custody and being questioned on suspicion of arson. The Met also confirmed they had been taken to hospital for treatment after five people were hurt in the fire.

An unnamed neighbour claimed the blaze was the result of 'gas canisters' catching alight in the 'factory'.

Cannabis factories often depend on numerous heating lamps which can cause electrical problems, with scores of lights and transformers used in the growing huge numbers of plants.

The incident took place in Hornchurch, east London, with nearby roads shut and reports of debris strewn across the area as flames 'billowed' out of the front of the building.

Witnesses said the front of the flats had been 'blown out across the street' while other buildings in the area 'were shaken' by the blast.

Smoke continued to 'pour' out of the front of the block for hours as the emergency service teams doused the building with water, with 30 people evacuated from the 41 flats.

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More than 70 firefighters have been at the scene of a blaze in Hornchurch after an explosion at a block of flats, pictured

Witnesses said flames were 'pouring' out of the front of the building, left, before emergency services arrived with a hazardous area response team, right

The fire brigade confirmed there was a partial collapse of the building, with the fire starting in a corner flat, pictured, according to the local council

Residents and bystanders, pictured, have been evacuated from the area as emergency services make it safe

Window frames were ripped away from walls by the blast, with rubble strewn across the grass outside the building, pictured

Serious internal and external damage has occurred at the flats, with all 41 emptied. Residents who do not have family to stay with will be found alternative accommodation, the council confirmed

The neighbour told EssexLive: 'Allegedly there was a cannabis factory on the ground floor. One chap had two gas canisters that somehow caught fire.

'The fire brigade were called and in ten minutes there were loads here. It looks like he lost control of it.

'The window frames were blown 70 feet.'

The Metropolitan Police declined to comment on the accusations and said it 'would not speculate' on the cause.

Ten fire engines were sent to the scene alongside specialist hazardous area vehicles.

The ambulance service confirmed it took four people to hospital.

Darren Lawrence, 47, told the Romford Recorder that cars passing on the A127 were struck by debris.

He told the paper: 'When I heard the noise I thought a lorry had crashed into the building. I rushed outside and there were people running around, frightened.'

Mr Lawrence added: 'I saw a man bleeding from his ears. Another had a laceration to his head.

'I and another man tried to keep people calm and away from the building. We used cones from the nearby building site to keep people and cars away.

A spokesman for Havering Council said most residents went to a local McDonald's restaurant, adding that measures will be put in place to ensure they have somewhere to stay.

The council spokesman said the explosion came from a ground floor corner flat, adding that 41 flats had been evacuated, with many residents staying with family and friends.

Eyewitness Jason Smedley, who is managing director of fingernail gel firm Nail Harmony UK, based around the corner from the flats, said he felt his office shake during the explosion and thought 'a lorry had driven into our building'.

He wrote on Facebook: 'Carnage!! Never witnessed anything like that before. We all heard a massive explosion.. ran round to see the front of the house across the A127! Pray that no one was in the flats. Stomach churning!!'

Speaking to MailOnline, he added: 'We felt the building shake and all of us went outside.

'We went down an alleyway and you could see the flames billowing out of the flat; the flames were pouring out of the front of this flat.

'The moment it happened we immediately though it was some kind of explosion.

'Originally we thought maybe a car had driven into the flats but now we think it must have been a gas leak.

'We were just trying to pull people back from the building to keep them safe. There were people screaming and crying everywhere.'

Much of the right side of the block has been blackened and charred by the fire as firefighters assessed the damage, pictured

Locals have been watching the drama unfold from behind a police cordon, pictured, with some given foil blankets

Reports suggest at least four people were injured in the incident, with London Ambulance Service and the Met Police also at the scene. Pictured are firefighters using an aerial platform to battle the flames

Witnesses said debris was 'scattered around' the area in the aftermath of the blast, with this window blown off the building

Witness Jason Smedley said part of the flats had been 'blown out across the road' due to the force of the explosion

Mr Smedley said the front of the flats had been 'blown out' across the road.

'We pulled people back and told them to get out of the way,' he said, adding that he and his staff brought people back to their office to give them shelter.

'Unfortunately there was a woman and her daughter, that were in the flat above, that heard the explosion, ran out, and we brought them back ... had just their dressing gowns on, so we just gave them tea and blankets. They've got nowhere to live tonight,' he said.

Mr Smedley added: 'By the looks of the flat where the fire was, if anyone was in it I don't think they could have survived. We are just praying it was empty.'

But there have been conflicting reports over injuries, with the Met Police claiming two people had been taken to an east London hospital.

A police spokesperson said: 'Police were called at 5.14pm on Monday, 23 January to reports of an explosion at a block of flats in Ardleigh Green Road. Hornchurch.

'Officers, the London Fire Brigade and the London Ambulance Service are currently at the scene.

As of 8pm the London Fire Brigade was still at the scene, pictured, as part of the ground floor flat remained alight

Thick plumes of black smoke have been pictured billowing out of the building, left, as the emergency services continue to work at the scene

It is still unknown how the explosion occurred and an investigation is underway with several police officers at the scene

The London Ambulance Service confirmed its first medics arrived at the scene within 'five minutes' of the blast

Motorists and pedestrians have been urged to avoid the area while the emergency services continue the operation

Police have also tweeted about the incident with the A127 road closed

'Two people at the scene were taken by London Ambulance Service to an east London hospital.

'Two people are currently being treated at the scene.

'One person presented themselves at an east London hospital with injuries. We await an update on their conditions.

'At this early stage officers are unable to confirm the cause of the explosion but enquires are underway.

'Residents are in the process of being evacuated from the building. The Local Authority has been informed and also on scene.

'Local road closures are in place. Motorists and pedestrians are advised to avoid the area.'

A London Fire Brigade spokesman said: 'Ten fire engines and 72 firefighters and officers are dealing with a fire and suspected explosion at a block of flats on A127 South Arterial Road, near Harold Hill, at the junction of Ardleigh Green Road.

A huge emergency services presence has been at the scene, pictured

Transport for London confirmed the A127 Southend Arterial Road has been closed while emergency services work (pictured)

There were 10 London Fire Brigade vehicles at the scene of the incident

'Part of a ground floor flat is alight.

'The Brigade was called at 5.14pm. Fire crews from Harold Hill and surrounding fire stations are at the scene.'

He added: 'The cause of the fire is not known at this stage.'

A London Ambulance Service spokeswoman said: 'We were called just before 5.15pm to reports of an incident at Southend Arterial Road, Hornchurch.

'We sent a number of resources to the scene including three ambulance crews, our Hazardous Area Response Team, a single responder in a car and a duty manager. The first of our medics arrived in under five minutes.

'We have now treated four patients at the scene and taken them all to hospital. We remain on scene.'

Transport for London said the A127 Southend Arterial Road was shut between Ardleigh Green Road and Bryant Avenue.