Octopus Energy paid more than £1m to customers in its latest energy challenge.

The energy supplier said more than 400,000 customers cut down their energy usage between 4.30pm and 6pm on Tuesday.

The scheme is designed to help reduce strain on the power grid by paying customers to switch off appliances.

The average customer was paid £2.50 in special points, which entitles them to rewards, for reducing their demand by around 60% on average.

The top 5% were paid an average of £15 in points.

Customers were paid 3,200 OctoPoints per kWh reduced, the equivalent of £4.

Octopus said the initial data showed it had reduced the UK's energy usage by around 250MWh - the same as the city of Liverpool going off grid for an hour.

The company said participation on Tuesday was similar to Monday, but as Tuesday's event was higher paying and there was 30% more energy reduced than the night before, less than £1m was paid out on Monday.

The so-called Demand Flexibility Service was launched by National Grid's Electricity System Operator (ESO) to help reduce peak demand during times when supplies are tighter than normal.

Octopus is the most active in the new scheme, though several other energy suppliers also took part in the system, which went live for the first time on Monday evening after being tested on several occasions previously.

By asking households to use electricity at slightly different times than usual, the grid does not have to pay very expensive power plants to come online and produce more power.

Experts consider it a first step towards a system where smart technology in people's homes helps to switch usage to off-peak times, saving households money and taking pressure off the power grid.