Professional ghost busters say they came under attack when they investigated a Harpenden pub.

The paranormal investigators were called to the Cross Keys, in High Street, after frightened landlady Maxine Brian was spooked by a series of ghoulish mysteries.

Mick Churchill, of Paraception UK, who entered the pub in the early hours of Saturday morning, said he and his team had been come under attack.

He said: “We each felt pressure around our throats in four different areas of the pub. Some corners went from black to blacker very quickly.”

Mr Churchill believes there is a supernatural presence inside the building and says he will produce a comprehensive report in the next six weeks.

Mrs Brian, who took over as landlady in March of this year, recalled one scary recent incident. She said: “I experienced four loud knocks on the cellar door one night. I thought it was my husband, but he said he had not knocked on the door."

She explained that she no longer goes down to the pub once it has been locked up at night – partly for fear of encountering the infamous hooded monks. They were first spotted in 1961 by the pub’s former landlord Reg Johnson.

The monks, who were apparently seen standing at the bar, were apparently spotted throughout the following decade and would suddenly disappear.