Trouble broke out following a party at the venue - hosted by a music company - that had an all-white dress code.
A 28 year old man was shot in the shoulder during the incident and gun shots were reported to have been shot into the air.
Sharriff Dacres, aged 22, of Cotterells, Hemel Hempstead, was found guilty by a jury of possession of a firearm and was sentenced at Harrow Crown Court on Friday (February 17) to seven years in prison.
video footage by WL
Following the incident, the home of his cousin Alexander Dacres, aged 27, of Tudor Avenue, Watford, was subsequently searched on June 14 (2016) and officers discovered white clothing, a gun, bullets and drugs.
He was found guilty of the following offences:
He was sentenced to a total of 14 years in prison. .
Detective Inspector Justine Jenkins, from the Beds, Herts and Cambs Major Crime Unit, said: “This violent incident was extremely unusual for the area and caused considerable concern among the local community.
“Many of those at the party on that day had travelled from outside the area to attend including some London rap artists.
“This was a complex investigation and officers worked hard to bring the offenders to justice. I am pleased with the sentences and I hope this sends a strong message to potential offenders that violent crime will not be tolerated in Hertfordshire.”