Frustrated firefighters have warned arsonists ‘enough is enough’.

Crews from Carlisle west fire station have been called to Higginson Mill, in Denton Holme, four times already this month.

The Cumberland News has previously reported on a rise in arson attacks at the block of flats, in which fires had been set in a rubbish bin block.

The latest incident saw yobs torch a portable toilet.

And, following the call-out at 5am on Wednesday, watch manager Bruce Wilson told The Cumberland News that it could not continue.

“The latest incident saw a portable toiletdestroyed,” he explained. “We had already had incidents on June 4, 10 and 12.

“Over the last six months or so we have had more than a dozen calls. We’re really getting frustrated now.”

As a result of the rising number of arson calls, an investigation has been launched involving Cumbria Police, Cumbria Fire and Rescue Service and the owners of Higginson Mill.

Mr Wilson continued: “We are available primarily for serious house fires and car crashes – and when we are responding to arson fires we are less able to respond to those. Calls such as this are a waste of time and resources as we have appliances responding to all these incidents.

“If you quantify it, it’s now costing the fire service – and therefore taxpayers – a lot of money.

“Each time we send four personnel and it takes at least an hour to get there, put out the fire and then get back.”

One of the ways in which the organisations plan to begin tackling the issue is through heightened surveillance – with the intention of catching and prosecuting anyone caught deliberately setting fires.