JUST 65 homes and businesses in the city centre were still without power at 9pm today following a blackout ten hours earlier.

All main roads have also been reopened, while traffic lights and some street lights are up and running.

Twenty-five firefighters tackled a blaze caused by an explosion in a sub-station which at one point had 3,800 properties without power.

It is still not known what caused the explosion at the sub-station, which is on Castle Road outside Ye Olde Trip to Jerusalem pub. However it is known that the power cut was caused by the fire which resulted from the explosion.

The blaze was so ferocious that firefighters struggled to get into the sub-station, which measures 10m by 10m. Thick smoke poured out of it for several hours.

At its height, postcode areas affected by the blackout included: NG1 1, NG1 2, NG1 3, NG1 4, NG1 5, NG1 6, NG1 7, NG2 1.

The drama unfolded at 10.52am, when Notts Fire & Rescue said they were told about the explosion at the electricity sub-station.

This report came two minutes after a power cut happened at 10.50am.

Engineers from Central Networks scrambled to find out the cause, which was said to be in the high voltage supply.

The gas mains were shut off as a precaution.

Firefighters in breathing apparatus were able to start entering the building at 2pm.

Station manager Neil Williamson, from Highfield Station, said:

"The premises were secure when the firefighters arrived. It is hard to tell what the cause is. It is unlikely to be suspicious. There was no one in the building at the time of the fire. It's difficult because the access is awkward.."

Firefighters were initially tackling the fire from the outside. They removed an external vent, which allowed them to pump foam into the building.

Rosie St John, manager of the Ye Olde Trip to Jerusalem, said: "I heard the explosion and it sounded like a bomb going off. I went straight outside and and there was a brownish smoke. There was people walking past and people coming out of the college after they heard the bang. The fire service seemed to come straight away and cordoned everything off straight away."

Firefighters were called to the Castle Heights building on Maid Marian Way to rescue a woman who was trapped in a lift during one of the outages.

James Parker, who works with the woman at not-for-profit legal aid group Refugee and Migrant Justice, said: "We were all staying in the office getting on with the usual stuff and all of a sudden everything went black. There was kind of a bang as well - and alarms everywhere. Fire engines coming down the road."

All city centre car parks are now open as usual.

Four NCP car parks were affected by the power cut. Power soon returned to Mount Street car park but St James Street, Arndale Centre and Queensbridge Road car parks were without electricity for about three hours.

During this time staff at the car parks did not allow cars into the sites and people leaving did not have to pay as barriers were manually lifted.