Ovo Energy has topped our poll for customer service for the second time running with more than 80% of its users rating its service as "great". At the other end of the scale, Npower remains last for the third poll running.

Almost 7,000 people voted in our latest energy company service poll, which we run twice a year in April and August. This time round, the top three rated companies were all smaller providers; Ovo Energy came top followed by Ebico and then M&S Energy. (For help switching provider, see our Cheap Gas and Electricity guide).

It's the second poll in a row Ovo Energy has topped and the second in which M&S Energy has been in the top three, showing how smaller and newer suppliers are giving the big six firms a run for their money. Ebico didn't feature in our last poll as fewer than 100 people voted for it.

Npower got the wooden spoon for the third year in a row with only 9% of customers rating it as "great", while a whopping 71% said it was "poor". This is significantly worse than the results from our April poll where 25% of customers said it was "great" and 49% said it was "poor".

It follows a string of widely reported errors over the summer including being found guilty of sending late bills to ex-customers, as disclosed by MoneySavingExpert.com, and then being found to be sending misleading payment demand letters, both of which could have contributed to its lowly score.

Scottish Power was rated as the second-worst company for customer service for the second-time running. Just 18% of its customers rated it as "great" while 55% said it was "poor".

The results

Here is the full table from our latest Energy Company Service poll:

Energy company service rating, August 2014(Results and ranking from April 2014 in brackets)

Rank Provider Great OK Poor
1 (1) Ovo Energy 82% (87%) 14% (9%) 4% (13%)
2 (n/a) Ebico 81% (89%) 16% (9%) 3% (2%)
3 (2) M&S Energy 46% (71%) 41% (23%) 13% (6%)
4 (5) EDF 48% (60%) 36% (27%) 16% (13%)
5 (6) E.on 43% (58%) 40% (28%) 17% (14%)
6 (4) Scottish and Southern Energy (SSE) 42% (46%) 41% (34%) 18% (20%)
7 (8) British Gas 35% (46%) 36% (33%) 29% (21%)
8 (7) First Utility 40% (56%) 24% (20%) 36% (24%)
10 (9) Scottish Power 18% (53%) 27% (30%) 55% (17%)
11 (10) Npower 9% (25%) 20% (26%) 71% (49%)
Order calculated by 0 points for poor, 1 for OK and 2 for great. 6,837votes in total – we've ignored providers with fewer than 100 votes. We've also excluded Telecom Plus/Utility Warehouse because it's a network marketing company, meaning its customers also spread the word and sell the product, which can positively skew its votes.The percentages may not add up to 100% due to rounding.

Unhappy with your provider's service? Switch

Martin Lewis, founder of MoneySavingExpert.com, says: "Many people don't switch because they think 'all energy companies are the same, so there is no point.' This isn't true, as well as the more widely publicised price difference – currently many could cut their bills by £200 a year – there are also big differences in service. So if you've been mistreated or pay too much, take them on by denying them your custom.

"It may seem early to think about gas and electricity bills but on the 'energy clock' we've already hit winter. When you switch it takes up to two months, so do it now and you should have the right provider in time for December.

"This poll makes particularly grim reading for Npower, which has been bottom of it for the last three polls. The company keeps telling us it's improving its service, but this hasn't been reflected in its customers' sentiment. The big issue for many are its horrendous billing problems – an energy company with bills more fictional than a Harry Potter book, doesn't help anyone."

'Significant issues with our billing system'

Beverley Harrington, a spokeswoman for Npower says: "We saw significant issues with our billing system, which affected how we looked after our customers. We're determined to improve and we're already making progress. For example, since June, we have reduced the number of late bills by over 75%, and the number of complaints we received by nearly 30%. 

"However, we know we still have a long way to go before we can reach the top spot and we're continuing to focus all of our efforts in this area."