ESSEX University is under investigation after music at its summer ball could be heard blaring out from around four miles away.

Organisers at the Students’ Union had previously agreed a ‘silent disco’ would take place at the bash after 2am meaning revellers would listen to music through headphones.

But Colchester Council was bombarded with complaints from residents who said thumping bass was heard through until around 4am on Sunday. Police officers also had to tell organisers to turn the music down after receiving complaints.

They attended at 2.25am, a force spokesman confirmed.

No arrests were made at the ball, based on the sports pitches of the university’s Wivenhoe campus from 9pm on Saturday.

The university was last night forced to apologise.

Mum Hollie Soper said she and her partner were kept awake at their Old Heath home - four miles away - by the racket.

Hollie, 26, said: “It was like club-sounding bass music. I phoned the police and asked what the noise was and they said it was that.

“They told us 150 calls were made in 40 minutes from people complaining.”

Hollie said she dozed off at 4am so didn’t hear the noise after that.

Unusually no complaints were understood to have been made by people living on the university’s doorstep in Wivenhoe.

The university posted on the Wivenhoe Forum to warn residents the event might cause some noise disturbance if the wind was blowing in the town’s direction.

A Colchester Council spokesman said: “The council has received a number of complaints, which it is investigating from a Licensing and Environmental Protection perspective.”

A university spokeswoman said: “The Students’ Union works before and during the evening with both the Police and Council Licensing to ensure it takes all the precautions it can to minimise disturbance.

“This included the main stage reverting to a headphone disco and the main sound system being shut down from 2am. “However there were smaller peripheral tents with amplified sound, and, it being a warm evening, there were people celebrating outside these tents.

“The University and Students’ Union’s relationship with the local community is extremely important to us and we are sorry for any inconvenience caused. We will continue to work with the licensing authorities to minimise the impact on the local community.”

Essex Police also insisted it only received a “very small number” of calls on Sunday about the ball.

A spokeswoman added: “Those related to loud music and one was from a member of the security team who was having trouble with some people who were trying to gain access but were being refused.

“Officers attended and liaised with the organisers who reduced the level of the music.”

The line-up included DJ sets , headphone disco, and a firework display.

The East of England Ambulance Service said it was not called to the event.