A motorway has reopened after a lorry carrying hay burst into flames following reports of a series of explosions - but lengthy delays remain.

Witnesses reported hearing loud bangs before the LGV caught alight under a bridge on the M2 near Blue Bell Hill.

Traffic is still moving slowly, but three out of four lanes of the M2 and the A229 at Blue Bell Hill are now open.

Robin Chappell, who was in the area at the time, tweeted to say there had been a "ground breaking explosion" as the lorry caught fire under a bridge.

A user called Tom added: "Chatham junction motorway stationary in both directions I have heard big explosion before smoke appeared."

Video: The M2 after a lorry caught fire. Video: Angie Peach

Another witness said there had been four explosions under the bridge.

The fire service said the blasts came from the tyres as they burst from the heat of the fire.

Crews used hose reel jets and main jets to tackle the flames, which engulfed the truck and trailer of the HGV.

The trailer is believed to have contained 26 tonnes of hay.

At 4pm, a spokesman said: "The fire on LGV is now out, crews have been working hard to target the hot spots in the hay bales using hose reel jets, to make sure the fire is fully out. The lorry and trailer have been completely destroyed by fire."

The spokesman said earlier: "Crews are making good progress in tackling the fire and are working hard to extinguish it."

Police and fire crews were called to the scene at around 11.45am.

No injuries have been reported and the cause of the fire is not yet known.

Police spokesman Jordan Bluer said earlier: "We were called at 11.44am on Tuesday to a report of a lorry on fire below a bridge on the M2 Coastbound at Blue Bell Hill.

"Officers are currently at the scene alongside the Kent Fire and Rescue Service.

"Both directions of the M2 are currently closed at Junction 3.

"The bridge at Blue Bell Hill, which runs over the M2, will also be closed due to the fire and will need to be assessed before being reopened."

At 6.12pm Highways England said all lanes reopened, but there were four miles of queuing traffic waiting to get through.

The scene was finally clear by 8.50pm.