Households were dealt a further blow today after a second major energy firm hinted at more price rises later this year.

Scottish & Southern Energy (SSE) joined British Gas in warning that as its costs are rising, these are likely to be passed onto consumers.

The firm says wholesale prices – the price firms pay for their energy – have risen by up to a third since SSE announced its last price rises in October.

The Big Six energy firms all raised prices last winter by an average 5.9%, adding £62 to the typical bill.

SSE says in its annual results this morning: "Future trends in energy prices for domestic customers will ultimately depend on what
happens in wholesale electricity and gas markets.

"Forward annual wholesale prices for electricity and gas have risen by around one quarter and around one third, respectively, in the
six months following SSE's October announcement of a price increase for household gas supply."

British Gas owner Centrica said last week it could raise the cost of household bills as its wholesale gas and electricity prices are around 25% higher than at the same time last year.

To make matters worse, British Gas yesterday pulled what was the cheapest tariff for most households, WebSaver 11, which typically cost £931 a year. It replaced it with WebSaver 12, at £955 on average per year.

Mark Todd, from price comparison site, says: "We expect prices to rise by 10% to 15% in the late summer to early autumn if market conditions remain.

"Rates are only heading one way at the moment and that is up. The later you leave any switch the bigger your next winter bill.

"Switch now to maximise savings and my advice is to go for a fixed tariff [where the price per unit is guaranteed] and lock down your rates."