Back-up systems on Britain’s electricity network “worked well” in response to the major power cut that brought widespread disruption to the country, National Grid has said.

Almost one million people in England and Wales were cut off from electricity on Friday after issues with two generators.

Traffic lights stopped working, Newcastle Airport fell into darkness and Ipswich Airport was affected by the power loss incident.

Major disruption also hit the country’s railways during the busy Friday night commute.

Frustrated travellers continued to experience disruption to services at London’s Kings Cross station on Saturday.

Speaking to the BBC Radio 4 Today programme on Saturday morning, Duncan Burt, operations director at National Grid, said the power cut was an “incredibly rare event”.

He explained that the two power stations disconnected from the grid “near simultaneously”.

Mr Burt said: “What happened then is our normal automatic response mechanisms came in to help manage the event, but the loss of power was so significant that it fell back to a set of secondary back-up systems which resulted in a proportion of electrical demand across the country being disconnected for a short period to help keep the rest of the system safe.”

He added: “Those events happened very, very quickly, in a matter of a few seconds, maybe a couple of minutes maximum.

“That sequence of events is entirely automatic, we think that worked well, we think the safety protection systems across the industry on generators and on the network work well to secure and keep the grid safe.”

UK power cuts
Temporary lighting was set up during the power cut affecting Clapham Junction train station (Yui Mok/PA)

Professor Tim Green, co-director of the Energy Futures Laboratory, Imperial College London, previously said that he believed the two disconnected generators were at Little Barford and Hornsea.

He said: “This event does not appear to be due to wind generation reducing owing to reduced wind speed.

“If that were the case there’d be reduction across many wind farms in [the] same area.

“The first generator to disconnect was a gas fired plant at Little Barford at 16:58. Two minutes later Hornsea Offshore wind farm seems to have disconnected.”

Mr Burt said the power cut had “nothing” to do with changes in wind speed or the variability of wind.

He also said National Grid was “very confident” there was “no malicious intent or cyber attack involved” in the incident.

He said National Grid would provide a “a detailed technical report” to Ofgem, which has already urgently demanded information as to what went wrong.

He added: “This will require careful study to make sure that we do learn any lessons that come out of it and that the next time this happens disruption is minimised and hopefully a lot less than it was last night.”

The scale of outage and the disruption it caused drew criticism from Labour and trade unions.

Shadow Business and Energy Secretary Rebecca Long Bailey said “Disruption on this scale is unacceptable.

“National Grid – which in May posted £1.8 billion in profits and increased dividend payouts to shareholders – must urgently provide a full account of what went wrong, and why.

“Integrating large amounts of renewable energy will require planned and coordinated investments in our networks,  which is why Labour has committed to taking the grid back into public hands.”

Manuel Cortes, general secretary of the Transport Salaried Staffs Association, said: “Having our rail network brought to a standstill in this way is totally unacceptable.

“We’ve seen thousands of passengers stranded, unable to board trains and a number of cancellations; others have been taken off trains and onto the tracks. We need to know why this occurred and the lessons to be learned.”

Rail Minister Chris Heaton-Harris praised the rail industry for supporting travellers during the disruption and thanked passengers for their “incredible patience”.

He added: “I have spoken to Network Rail and operators today and agreed we must now focus on learning the lessons, including how we can improve our resilience, capability, and in particular, ensure all passengers get the very best, up-to-date information during such extreme events.”