A former energy secretary cautioned last night that Ed Miliband's intense focus on wind and solar energy could put Britain in jeopardy of experiencing blackouts, especially as the country's gas reserves have dwindled to 'worryingly low' levels.

As temperatures dip below freezing again this weekend, the chief executive of Centrica, the parent company of British Gas, announced that the nation has less than a week's supply of gas available.

The alarming alert follows just days after the UK nearly experienced power outages on what was described as the most strained day for the GB electricity market since 2011.

On Wednesday, the National Energy System Operator in the UK alerted electricity suppliers to increase their production levels. 

It cautioned that the country lacked an adequate buffer to maintain its power supply, and experts subsequently indicated that the power market was 'within 580MW of needing demand control or facing a blackout'.

The national grid struggled with a lack of wind power, no solar power during the night and interconnector outages. 

In order to address the deficit, grid operators were compelled to pay as much as 50 times the usual electricity prices to maintain the operation of gas power plants. Energy Secretary Mr. Miliband is advancing 'bold' initiatives aimed at achieving 95 percent clean energy in the UK by the year 2030.

Last night, Claire Coutinho, the former energy secretary in the previous administration and now a key opponent of Mr. Miliband, voiced her criticism of Labour's initiatives aimed at achieving net-zero emissions. 

She remarked, "Ed Miliband's fixation on wind and solar energy, instead of ensuring energy security, will result in financial losses for us, make us reliant on foreign imports, and expose us to the threat of power outages." 

"As I mentioned last year, we should focus on constructing additional gas and nuclear power plants to ensure we have affordable and dependable energy."

On Thursday, the levels of gas stored at UK facilities were 26 percent lower compared to the same timeframe last year, resulting in storage being approximately 50 percent full. 

Gas inventory levels are facing strain due to the recent cold weather and the cessation of Russian gas pipeline supplies via Ukraine at the end of last month.

According to data from National Grid, natural gas made up slightly more than 55 percent of the UK's power generation yesterday, while renewable energy sources fulfilled approximately 10 percent of the nation's energy requirements.

The United Kingdom has one of the lowest levels of gas storage compared to other major European nations, with the ability to store gas sufficient for 12 typical days or 7.5 days during peak winter demand.

Germany has sufficient supplies for 89 days, while France can sustain itself for 103 days, and the Netherlands has enough resources for 123 days.

Last year, energy production from significant fossil fuel power plants accounted for just over 25% of the overall total, whereas renewable sources, particularly solar energy, saw an increase, along with a rise in electricity imports.

A spokesperson for No10 stated yesterday: 'We are assured that our gas supply and electricity capacity will adequately meet demand this winter, thanks to our varied and robust energy system.' 

They stated that reports suggesting the UK was on the brink of an energy blackout are 'false'.