THIS is an urgent energy warning: gas and electricity price hikes are back. To beat this, you need to act at speed. For the first time in two years one of the big six energy companies, Scottish and Southern, has announced a major price hike with gas prices up 9.4 per cent on average from December 1.

Industry insiders believe more will follow suit, blasting energy prices sky-high at the worst time possible. This is an urgent plea to take a few minutes, save yourself hundreds of pounds, and sort it now before it’s too late.

What’s happened?

While S&S’s price hike will directly affect more than three million customers, tens of millions more are likely to be hit too, as this shock price rise has changed the game.

Beforehand, the general consensus was there would be some small price rises, up to five per cent-ish, in January. Now, insiders believe companies could bring in bigger hikes much earlier.

After all, if energy companies had a voice, it would be “baa” as they have a herd mentality – when one moves others follow. In the past, when one company raised prices I yelled “don’t switch”. This was because you could find yourself leaving a company that had raised its prices for another that was just about to do so.

That said, one big six energy company, EDF, has pledged that it won’t increase standard energy prices before next March. Yet the likelihood is its prices will rise in March – and the delay is almost certainly an attempt to retain competitive advantage in the short-term and attract switchers.

The truth is, if you are on EDF’s or any other company’s standard tariff anyway, you’re already likely to pay hundreds of pounds more a year than you would by switching to specialist online billed deals.

The urgent action you need take

These days, we have a two-tiered pricing system.

Most people are on standard tariffs which, in the average home, mean bills of about £1,200 a year. Yet the energy-savvy only pay about £900 for the same usage, as they have special online billed tariffs which are massively cheaper.

This £300 annual saving is available to anyone who is on the internet. All it means is you get billed by email rather than by paper (though don’t confuse it with having online access to your account – it’s specifically about how you’re billed). So if you’re not already on an online tariff, it’s worth switching as soon as possible, for three reasons:

● Winter is coming. Although it takes minutes to find the cheapest tariff, changing over to it will usually take a couple of months. Switch now and by the end of December you should be on the new pricing. Leave it until the cold weather settles in and you’ll be paying more than you need to until spring. It’s the same gas and electricity. The only difference is customer service and billing.

● Cheap online tariffs are disappearing. Many of the lowest tariffs get closed to new customers after a few months. The longer you leave it, the more you will pay.

● Online tariffs should save you money, even if rates go up. This is because the differential is so big, the saving compared to what you would have paid is huge.

Find your cheapest rate in five minutes

When you switch, it’s the same gas, the same electricity, the same safety – only price and customer service change, so it’s a no-brainer.

Just use a Consumer Focus-approved comparison service, such as energyhelpline, energylinx or uswitch, who operate online and over the phone. All you need is one or two past bills and your address.

For a bonus, go to comparison sites via my website, moneysavingexpert.com/gaselec, and you will get up to £30 cashback and a crate of wine that you wouldn’t otherwise get. They do this because so many are switching that they fight for custom by offering incentives.

Is it worth getting a fixed deal?

A fixed tariff (often incorrectly called a “capped” deal) is a price promise that the rate you pay won’t change for a set amount of time – usually a year or two. Of course, your bill will still go up and down depending on your energy usage.

The cheapest fixed tariffs are more expensive than the cheapest variable tariffs, yet online fixed deals are still much cheaper than the bills most people are paying.

My rule of thumb is the more that you are worried about affordability if prices rise, the more you should consider fixing, even though there’s no guarantee that it will be the cheapest route in the long term.

It’s worth noting that fixed deals usually have early exit penalties of about £50, so in the unlikely event of prices dropping elsewhere, you would have to pay the penalty before you could switch to a different deal. Effectively, this is the cost of “insuring” against price rises.

Dos and Don’ts of switching

Don’t assume dual fuel is cheapest. Check out separate gas and electricity as well as together.

Do switch to a monthly direct debit. You pay a fixed estimated amount each month, cutting your bill by a further five to ten per cent.

Do take a meter reading.

Energy estimates are often way out and mean a higher direct debit.

Don’t confuse the direct debit amount with the cost. You may switch to a cheaper rate, but pay a higher direct debit because it is inaccurate.

Do avoid prepay meters if you can.

They’re far more expensive than cheap direct debit tariffs.

If you must have a prepay meter, they are included in the results of some comparison sites.

DO consider a financial hardship tariff.

Some utility companies will offer you special deals in cases of severe hardship. Call them and ask.

Do cut your energy use. Don’t leave the heating on full while the windows are open, and take precautions to keep your home insulated.

Good deals

★ Get back lost Tesco vouchers. It’s possible to get them reissued, as far back as 2008.

Collectively, MoneySavers from my site have already uncovered more than £3,000 of vouchers. Just go to tesco.com/clubcard, enter your details and click “Your Vouchers” to view unused vouchers. My full guide is at moneysavingexpert.com/losttesco

★ Secret £1 train tickets map.

Megatrain.com sells thousands of £1 singles for Virgin, South West and East Midlands train routes (plus 50p booking fee). There’s a map or destinations list on its site: we suspect because its system has merged with £1 Megabus tickets, and train fares draw people in. We’ve got a full £1 plus fares list and route map, and you can still save even if it covers only part of the trip. See moneysavingexpert.com/trains