Thousands of people have taken to the streets in the UK in protest against the sharp rise in energy prices, as a cabinet minister said the government could not “completely nullify” the increases. Demonstrations took place on Saturday, including one near Downing Street in central London where crowds gathered to hear speeches, including from former Labour leader Jeremy Corbyn. Other protests took place in cities including Cardiff and Birmingham. They follow a major increase in the energy price cap on Friday, with average household gas and electricity bills rising to £1,971 a year. A further jump in October could take the cost up to £2,600. Groups including the Trades Union Congress and anti-poverty campaigners have voiced alarm at the changes, and said that when combined with increasing inflation and low pay, it could push people into “impossible choices” between heating their homes or eating. A spokesperson for the People’s Assembly Against Austerity, the organiser of Saturday’s series of events, said: “Public outrage over the cost of living crisis is growing fast, and our response is gaining momentum.” Corbyn said: “I’m meeting people who are terrified of the next bill, so the very least we need is a price cap on energy, and then we need to say, well look at the profits of energy companies and look at the difficulties of people living.” The price increase is driven by more demand on energy as economies recover from the effects of the Covid pandemic, with supply unable to keep up. Russia’s invasion of Ukraine has also exacerbated the issue, with some countries stopping or limiting their purchase of Russia’s oil and gas. Ministers have announced a council tax rebate for April and a £200 loan available from October to help soften the burden, but the Labour party has said there should be a windfall tax on oil and gas companies to help provide support to those in need. In France, the government has limited energy bill increases to 4% this year. Speaking on Sky News on Saturday, the Northern Ireland secretary, Brandon Lewis, said: “We [the government] can’t completely nullify the impacts of the global markets and global pressure, for example, on energy, which is obviously the main focus at the moment for most people. “But we will put in the support that we can, as and when we can, as I say, looking …… across the board at what we’re doing with the public’s money.” Labour said the government should bring in laws to keep prices down. The shadow transport secretary, Louise Haigh, said: “We would be meeting with oil and gas companies to make sure that it happened and, if it didn’t, then we’d be putting in legislative measures to make sure that it did. “I think we do need to see legislative measures if North Sea oil and gas companies, petrol retailers, are experiencing record profits and not passing any of those savings on to customers.” She said she was shocked that the increase in national insurance contributions was going ahead when people were having to deal with other spiralling costs. “It frankly beggars belief when we think about what people are having to pay over the coming weeks and months, that the government would not be doing much more to support people, let alone making things harder,” she told Times Radio. Amid a renewed focus on energy, the government’s strategy on the issue has yet to be revealed – weeks after it was due to be announced. Reports in the Times suggested that Boris Johnson was considering trebling the amount of onshore wind power by 2035, despite many Tory backbenchers opposing it. Nuclear power is also expected to feature heavily. Asked why there had been a delay and whether he supported onshore windfarms, Lewis said: “It’s complicated work to look at how we can have an energy policy package that’s holistic, that looks at all parts of energy, and we can become more domestically self-supportive on that, which will have a positive impact on prices. It’s right they take that time to have a look at it.”