FARMERS today said it was “quite rare” for straw stacks to suddenly burst into flames - but it can happen.Two fires on the Felixstowe peninsula this week have been the subject of the phenomenon, causing the loss of bales worth several thousand pounds.

FARMERS today said it was “quite rare” for straw stacks to suddenly burst into flames - but it can happen.

Two fires on the Felixstowe peninsula this week have been the subject of the phenomenon, causing the loss of bales worth several thousand pounds.

Police and fire crews said neither of the fires at Levington and Bucklesham, which destroyed in total 96 tonnes of straw, was being treated as suspicious.

While it is not known exactly how they started, experts say spontaneous combustion is possible.

Brian Finnerty, spokesman for the National Farmers' Union, said straw stacks could catch fire on their own because of the extreme heat generated by chemical reactions within the stacks.

Mr Finnerty said: “It can happen but it is quite rare.

“Sometimes thermal probes are put into the centre of the stacks to see what the temperature is and make sure the stack is not at risk because of the heat which can build up inside.”

Experts say spontaneous combustion can take place when straw is gathered in wet or is poorly ventilated, or moisture from the ground rises and makes the stack damp.

The fire at Levington took hold of a stack in a field next to the Old Felixstowe Road, while the one at Bucklesham was near the primary school in in Felixstowe Road.

Mr Finnerty said: “Our biggest problem though at this time of the year is attacks by arsonists.

“There have been attacks even on the most isolated stacks and if someone is persistent and determined to do it, it is really hard to protect against it.

“Stack fires can be dangerous for firefighters and tie up their resources when they may be needed elsewhere, cause damage to the environment and cost thousands of pounds. It is a big concern.”