British consumers face the steepest increases in energy bills in Europe this year, as continental suppliers squeeze customers for extra profits.

Households in the UK are braced for fuel-price increases of 15 per cent -20 per cent, while consumers in Germany, Holland, France, Spain and Italy will see gas bills go up by about 5 per cent and electricity by about 7 per cent, according to figures compiled exclusively for The Sunday Times by Energy Advice, a market analyst.

Earlier this month, Npower hit customers on its standard tariff with rises of 17 per cent for gas and 12 per cent for electricity, and other firms are expected to follow suit in the next few weeks due to sharply rising wholesale energy costs – electricity hit a record high last week.

However, Npower’s parent company, RWE of Germany, is shielding customers in its home country from these increases. In fact, some German RWE customers saw a 5 per cent decrease in gas bills in November.

Though other suppliers in Germany have increased tariffs, the overall rise this year is about 3 per cent for gas and about 7 per cent for electricity, according to Energy Advice.

In France, the government-controlled supplier announced a mere 4 per cent increase in gas this year while electricity prices were kept on hold. Reports from Holland and Italy indicate rises of between 3 per cent to 5 per cent for both gas and electricity.

Mark Todd of comparison firm Energy Helpline said: “Britain has a deregulated market compared with most of the rest of Europe, which means we get bigger increases and bigger cuts. This gives European suppliers an ideal opportunity to skim off a bit more profit without customers noticing.”

Of eight European countries, including France, Germany and Spain, Britain saw the highest rate of increase for domestic gas between October 2005 and October 2006, when wholesale prices were rising – bills went up an average 39 per cent. It also had the sharpest decreases a year later as the wholesale price fell and tariffs went down 16 per cent.

Despite this, gas in Britain costs about 16 per cent more than in October 2005 if you exclude taxes, and electricity is up 15 per cent. This suggests suppliers have used market volatility in Britain to boost profits.

The Spanish firm Iberdrola, which supplies more than 5m UK homes through the Scottish Power brand, is making 22 per cent more profit for each UK customer than in its host country, according to Energyhelpline.

Energy firms claim bills are in general lower in Britain than on the Continent, but they nevertheless use several ploys to keep us paying more than we should. We show how you can beat the tricks of the trade.

Bag a secret web deal

One of the best tariffs is currently Scottish and Southern’s Price Fix, which caps rates until November 2008 – but you wouldn’t know it if you use online switching sites. The firm has withdrawn the deal from comparison sites because it is oversubscribed, but it will still be available on its own website until tomorrow.

The average bill on SSE’s Price Fix is £744 a year, compared with £740 on the best variable deal, the British Gas Click Energy 4 tariff – although the latter is likely to go up as British Gas is expected to announce price increases soon.

Scottish Power also officially withdrew its Price Fall 2008 tariff last week, but it was still available on its website on Friday.

Beat the regional apartheid

Energy firms have traditionally charged more in some areas than others, but the differences were more marked for electricity than gas. However, Npower and SSE now charge up to £45 more for gas in areas like London and the East Midlands than for customers in the southwest or northwest.

Suppliers blame distribution costs for the regional differences, but new research shows this argument does not bear scrutiny. The most expensive region tends to be the north east of England where the incumbent supplier, Npower, charges £1,043 a year for standard dual-fuel customers – £100 more than in the southeast.

As much of Britain’s energy arrives in the northern parts of the UK, distribution costs do not explain the difference.

The best way to beat the regional apartheid is to switch, but if you don’t want the hassle of constantly moving, Scottish & Southern Energy tends to be consistently competitive in all regions.

Demand back overpayments

Energy firms often overestimate your bills, and if you’re on a direct debit tariff, you could be paying £150 to £200 a year more than you should be.

About 30 per cent of UK households’ gas bills are based on outdated meter readings, according to comparison site Money Supermarket.

Check your own meter on at least a quarterly basis and log the details online. You can use your supplier’s website even if you’re not an online customer. If you find you have been paying too much, demand a refund. If this doesn’t resolve the problem, then complain to Energywatch, the energy watchdog (energywatch.org.uk).

Beware pricey fixed deals

With rising wholesale prices, energy firms are keen to push their capped-price deals, which promise to safeguard against bill hikes. However, these are set at a premium and not all are worth it. Other than SSE Price Fix 2008, current deals are Eon’s price-pro-tection tariff, which is capped until October 2009 and costs an average of £904 – £164 or 22 per cent more than the cheapest variable deal.

EDF’s fixed tariff until August 2010 costs about £963 – £233 or 31 per cent more than the best deal. Analysts said prices are unlikely to go up this much, but there are no guarantees.

Npower has recently launched a three-year fix that has a 7 per cent premium on top of its new standard prices, bringing the average price to above £1,080. Joe Malinowski at The Energy Shop said it is not worth protecting past 2009 as forward wholesale energy is trading about 5 per cent lower in 2010.